Definitely take care of yourself first and talk this over with your psychiatrist.
You might feel better letting your ex know how you feel, you might not. Are you equipped to deal with horrible things your ex may say?
I say this from experience. My ex and I had an abrupt ending a while ago, and a bunch of our mutual friends, she, and I are going to meet up in the near future. Because I feel uneasy about it, since there are unresolved issues, I sent an email to her about it. She sent a very nasty and crazy one back, accusing me of being dramatic and making wild accusations left and right.
It hurts. It still hurts very badly. I don't know if I could've handled it if I were deeply depressed. I can look at it now and realize how wrong she is for me, because she was a big, self-righteous bitch in the whole thing (I'd still take her back, though, if she ever explained that email and the ending), but I'm in a lot better place than I was when I was depressed.
You can't control your ex's actions or predict them. I'd consider the possibilities before you do anything. Part of me wishes I would've not bothered trying now.