I know how you feel but the first thing you have to do is forget her, and the second forget the suicide thing.

What you need is to find something that fulfill you, some hobby, some group of people to hang out, a sport, something that make your mind don't think in 'the good old times'.

Also if enough time have passed since you broke with her, maybe you must look for another girl.

Live is hard, but we must be more.