The most important thing to realize is that each of these stages is normal, and that so long as you are progressing through them (even slowly) then you will eventually reach acceptance, or healing. Sometimes people seem to get stuck in one stage, or to skip stages. If psychological theory is right though, you can't really skip a stage--you won't really heal and move on unless you have been through all of them.
The initial state before the cycle is received is stable, at least in terms of the subsequent reaction on hearing the bad news. Compared with the ups and downs to come, even if there is some variation, this is indeed a stable state.
And then, into the calm of this relative paradise, a bombshell bursts...
Shock stage: Initial paralysis at hearing the bad news.
Denial stage: Trying to avoid the inevitable.
Anger stage: Frustrated outpouring of bottled-up emotion.
Bargaining stage: Seeking in vain for a way out.
Depression stage: Final realization of the inevitable.
Testing stage: Seeking realistic solutions.
Acceptance stage: Finally finding the way forward.
This model is extended slightly from the original Kubler-Ross model, which does not explicitly include the Shock and Testing stages. These stages however are often useful to understanding and facilitating change.
One of the hardest things I experienced was that my husband and I often progressed through these stages at different rates, or in different ways. So he wanted to distract himself and avoid thinking about our baby at the time when I wanted to wallow in my grief and just talk about it... or he was angry at the world at a time when I was fixated on trying to just get pregnant again.
You should not feel pressured to grieve in a certain way, nor to be "all better" by a certain time. Each stage will manifest in different ways in different people, and in different kinds of circumstances, and things that are helpful for one person may not be helpful for another. However, here are some examples of how the various stages might manifest when grieving over miscarriage. (If you have something to add, please comment and I will add it here in the post.)
The news of fetal demise or the onset of physical miscarriage is overwhelming. It's common go to into an adrenaline-filled "fight or flight" mode, with moments of startling clarity (choosing whether or not to have a D&C, arranging babysitting for other children, or calling in sick to work). It's also common to completely freeze up and be unable to do or think anything. You may not be able to cry at this stage...or you may not be able to stop crying.
Trying to convince yourself that the baby didn't really die, or that you never were really pregnant. That something has been misdiagnosed. That you should get a second opinion, or a third. That if you just hurry and take the right herb or medication that everything will get better. This stage might also be called "Distraction," as some people (notably husbands) seek to avoid thinking about the loss. Sometimes this manifests in wanting to get pregnant again as soon as possible (as though you were always just pregnant). Sometimes it manifests in wanting to never get pregnant again.
Casting blame at anyone and anything that might possibly have contributed to the miscarriage. It's common to be angry at your spouse, with the rationale that they contributed the 'flaw' that caused the miscarriage, or that they are not supporting you in the way that you want them to. You might be angry at yourself, feeling that your body is broken because it did not keep the baby. You might be angry at the baby, or at God. You probably will be angry at anyone else in the world who has children, or babies, or is pregnant, or who takes those things for granted, or who has never lost a child. You will most likely be upset with anyone who is insensitive to you.
At this point it is normal to think about anything that you could change about the status quo, and to fixate on changing them. It's common to feel disgruntled about your marriage, to feel like if you had a different spouse things might be better (you might have more money or live in a nicer place or have more friends or better support or even, most literally, that procreating with a different partner might have avoided miscarriage). This stage may involve wanting to try to conceive again right away. You may try to 'make deals' with God (things like "I don't want to miscarry again so if I'm just going to miscarry then don't let me get pregnant again").
As the graph indicates, this is an inactive state. Many people feel lethargic when they are depressed. More than feeling 'sad' per se, they often simply feel nothing. It is common to withdraw from social activities--sometimes to avoid questions, possibly to avoid the possibility of feeling happy (many of us feel guilty over being happy about something, as though it indicates a lack of love for the child we are grieving).
Testing is the beginning of acceptance. I think it's something like learning to roller skate--with false starts and falling down. There are a few attempts to move into 'acceptance' and some of them will fail miserably, which will drop you back into depression or anger or some other stage, and then you'll have to push forward again. You may need some time to gather yourself before you feel ready to try again. Eventually however, with continued trying, you will reach the final stage of
This is what we refer to as 'healing.' As with any wound, there will be a scar. You will never return to being the way you were before the miscarriage, but you will find a new 'normal' and you will reach a point of being able to live life, get things done, and even be happy. You'll be able to hear pregnancy announcements, see pregnant women, or hold infants and not be depressed. You'll be able to look back at your loss without fixating on it, and you'll be able to look forward into the future, and to move into it. Sometimes people refer to this stage as 'closure' but it's broader than that. It's not closing the book on what happened, it is accepting and validating it, and moving forward with life anyway.
Sometimes things drop me back into grieving for my children (although the grief is not so intense nor does it last long). Perhaps it's seeing a child who is the age my angel would have been. Perhaps it's meeting someone whose due date is near when mine was. Sometimes it's being with someone who is going through a loss of her own. Sometimes it's looking at my own children, and wondering how our family dynamic would be different if those other babies had lived. Because, even though I am a whole and healthy person, my experiences of loss have made me into a different person than I would have been without them.