The 5 phases of grief do not come to you in any specific order. Just because you went through the phase it doesn’t mean that you will not be hit with it again. There is a different aspect of the anger that you haven’t addressed.
There are different types of losses. You may be going through the loss of a special person, but however, there are losses that occur that you don’t realize that require processing just as much a loss of a loved one. There is a loss of a home, Job, finance, friend who moved away or a relationship that didn’t work. A divorce. The key does not disregard these losses as something you don’t have to process. Loss is a loss.
Once you have acknowledged what it is that you are going through. You can take a deep breath, don’t beat yourself up about it and carry on.