Have you considered keeping a private, handwritten journal that accounts your feelings? That's not to discourage you from posting here--by all means, keep doing so! We want to listen and help!--but in your private journal you can be as happy, sad, nasty, or kind as you want to be about your thoughts towards this relationship. I've done it (well, typed it on the computer!) but it helped immensely. Looking back on how I felt at the beginning of the relationship, the middle, the end, and the aftermath, I especially see what thoughts were just, and what others were silly even if they didn't seem so at the time. It has brought me a great deal of clarity.
Another thing that does wonders...go do something now, today, something that you know will make you happy, preferably something not having to do with your guy. For me, it's being close to nature, and photography. Nothing brings me more instant joy and comfort than walking around a beautiful garden filled with flowers and butterflies and taking pictures I can frame. What's your thing that makes you happy?
P.S. Feel free to peruse my photo gallery if you want...it's linked here, just click on the little earth to the left. Maybe you'll find something there that makes you smile, even if only for a little while?