You need to seek therapy. Immediately.

The fact that you regret what you’re doing is a good thing and you need to let that carry you into action. You know what you’re doing is wrong, so I won’t shout at you about that. But the solution to it is to stop, and hopefully not by killing yourself.

You need to fix your issues, yes, but you need to do it away from your girlfriend. Chances are good that it’s going to take you a long time to find a fix, and you should not ask your girlfriend to stand by you when your behavior puts her at emotional, psychological, and physical risk. My advice is to step away from her (break up, move away from each other), then seek treatment.

It’s possible. Even with your struggles it’s clear that you want to change. As long as someone else is at risk, you need to start the process now, not later. You can do this. For what it’s worth, this internet stranger believes in your power to change.