Would it help to say "don't do it"? :) Hurt yourself, I mean. You've kind of been through enough and you need to heal yourself, not hurt yourself further, agreed? How about spoil yourself rotten instead? :)
I know I haven't had your day (mine was quite terrible enough, thank you very much!) and I probably can't fully appreciate the depth of your depression/annoyance or whatever else you're struggling with - but every once in a while everyone hits rock bottom. You just kind of have to accept it, I guess. It's just one of those days. I have a child with Asperger's syndrome and last Friday (13, he he), when there was full moon, I just knew he was going to have a bad day. And it didn't look bad at the beginning - like you said, roller-coaster - but it ended disastrously and it really helped me that I came prepared and sort of shrugged it off as "one of those days" everyone has to keep you grounded.
The day you had today will probably have its offspring some time in the future - but then there will also be good days and you know that, it's just hard to remember right now. Like - there will be new movies to see you could look forward to (shallow, I know, but when I'm down, I'll take whatever I can get), great books to read, interesting fic ideas to realize and perhaps opportunities to say that "fuck off" to someone who really irritates you in this world. ;)
You just have to make it through the deep and the coast is near. Hug - and a pull to the shore. There, all better! ;) (my, how presumptuous of me!:))