Don't worry, I did that once. Eventually I just didn't bother reading the comments and didn't say anything about it, and people forgot. If you just move on and don't acknowledge anyone who says anything about this, then people will forget.
The important thing is that you can learn from mistakes. What I'm trying to say is that you should lurk more next time.
You either grow thicker skin, or you stay off the forums and go live in a cave for the rest of your life. Also, if you seriously consider killing yourself over such a small thing as this, then I highly recommend seeing a therapist about your incredibly low self esteem.
Man I really don't want to sound rude or anything, and please don't take this the wrong way. I understand being depressed and having depression already, but if a couple of people being slightly rude to you deviantart makes you suicidal, you are gonna have a REALLY hard time with life.