I'm the same way when it comes to forgiving myself - I just recently realized how judgemental I really am when it comes to things I do wrong (so I'm just now starting to work on it - or at least try to). I'm going to address that issue with my counselor when I see her next week. Are you seeing a counselor or have you thought about seeing one - maybe they can help you work through some of that stuff??
I've noticed that I tend to go through phases - just like you describe - anger, sadness, peace and then it repeats itself. There are times when all I want is work on myself (visit SR daily, work in my self-help book, journal, etc. - really kind of obsess about it a little) and then I go into a phase at times where I'm sooo sick of having to work on myself and just let it all go (which usually doesn't end well because I tend to fall back into depressive, self-loathing mode). But I think noticing your phases, moods and thinking patterns is the first step to getting better (because then you can plan ahead and figure out what you need to work on).
The book (DBT skills book, M. McKay) I'm working with right now (it deals a lot with mindfulness - so maybe not for everyone) suggests to let go of judgements by using a visualization technique - i.e. imagine sitting in a field watching your judgements float away on clouds. It also suggests that when we spend a lot of time obsessing over our thoughts and judgements, it's easy to get lost in fantasies about how the world should be, so it's important to recognize and seperate our judgements and fantasies from what's really happening in the moment (i.e. become aware of your physical senses - what do you hear, see, smell, touch, taste). (Haven't tried any of this yet - so I'm not sure how this works).
Another thing that might be helpful is using self-affirming statements, such as: I might have some faults, but I'm still a wonderful/ good/ amazing person - I accept myself for who I am - each day I do the best I can. You can put self-affirming statements on sticky notes and post them on mirrors or computer or places where you will see them A LOT.
I'm not sure if this was of help (I'm still kinda trying to figure all this out for myself).
Just remember to accept yourself for who you are!!! It is ok to feel your feelings and you can use your past "mistakes" and learn from them.