As the Bible states, God is all-seeing and knowing. I'm quite sure he would make the proper judgement concerning your situation 
However, I have never read a passage saying anything along the lines of what Joe's just posted. Give some proof.
I still believe it's forgivable under certain circumstances, but I do agree that it should be treated as "unforgivable" in most cases. You're basically taking things into your own hands and not leaving decisions that cannot be made by man up to God. And since sins can only be forgiven if you're repentant, suicide can't really be forgiven; it's hard to repent when you're dead.
Here's a decent article on the issue.
