Maybe if you stopped pursuing peace of mind you might actually feel better?
You know that what you have been doing hasn't been working for you. So simply stop.
Easier said than done in some cases. I know that in my case, my way of trying to get a handle on things or control things often makes me feel like crap. It works very well for some technical problems in some contexts, but when applied to the activity of my mind and emotions, it just won't work.
Reality just wont play by my rules, it seems. So, what do you do? For me, for now, I simply decide to let go and focus on what I enjoy.
I think Alex has a point in asking about what you want specifically. Your mental map for experiencing, having, continuing to have, and failing to beat this problem is very detailed. It looks like you could easily write reams and reams about it if you wanted, right?
So, it'd probably be beneficial to start playing around with the ideas of experiencing and having what you want. If you had a perfect day, what would that be like? If you experienced some of these emotional problems and it really wasn't a problem for you, what would that be like? If you lived with peace of mind, what would that be like?
Maybe the mind is like an animal, you coop it up and do all kinds of stuff to it to try and make it work by your rules, and it isn't very peaceful. It gets all riled up, frustrated, and angry. Maybe you should just give your mind room to do what it likes?
Your ideas about how to have, experience, and maintain peace of mind may have nothing to do with what actually gives your mind peace. You are not your mind, you do not consciously know everything about your mind.
Study your mind, find out what makes it feel peaceful, and let it have that.
Stalk feelings of peace throughout your day. Don't try and create them, just discover them and study the tracks that led your mind to that place. That is, make a more and more detailed map of peace of mind ... how it occurs naturally for you.