I'm definitely not one to talk about life and future plans, but I can talk about suicide.
Short version: Don't.
Long version: Suicide is very difficult to consider. Not only do you not get to experience life past that point, but anyone in your life that cares about you, even remotely, would be affected strongly. It can have incredible ramifications.
I've had a noose fail after nearly an hour and bleach make me horribly sick for a week, but neither worked. I came to conclude that whatever controls the world must have wanted me to remain alive for one reason or another. Very few people know the extent of the trauma those failed attempts have left me with. But if I did succeed? It would have been trauma for everyone else in my life, and even in middle school, when these happened to me, you talk with hundreds of people every week.
Even at my most emotional, just after those attempts, I could think of just as many reasons to struggle on through life than to stop it there. I'd never see my nephew start school, I'd never see my sister after she moved, I'd never date...
If the worst were to happen, and you did become separated from your girlfriend, find a family member or friend you're close to. They will give you the strength and the reasoning to bypass your emotions when you can't. But more importantly, look ahead with the deep hope that it won't happen. Also, keep a suicide hotline in your phone, in case you ever become mortally worried about your sanity.
And be careful :3