Bin there, done that, and hurt a lot of people into the bargain.
But this isn't one of those "my angst is bigger than your angst" posts; I feel for you on this one.
Love may be the most wonderful thing in the world, but it can also hurt like hell. I'm surprised it's not a proscribed drug, given its potential to wreck one's life!
And, Guest, no, you're not pathetic - even if people who mean a lot to you are telling you so right now, it's only because they're hurt too. You're a valued human being, and tghe fact that you're able to express yourself here and acknowledge that things haven't gone the way they might shows that.
Things WILL get better, but meanwhile, get out there, sing and play, and don't whip yourself too much. We all fuck up - it's in our nature. And who's to say that hingsight might not one day put an entirely different perspective on today's misery? Good luck.