I am totally depressed, answers are very much appreciated?

[Paul]

Me and my girlfriend have been together for almost a year, I love her so much and I couldn't help asking it on yahoo answers, I'm just so depressed and out of ideas. I am really committed to her and we are moving towards marriage.

We almost broke up like a month ago but we managed to get along again, I sworn to change my bad habits and will be a whole new person since. Yesterday, my gf logged in into my twitter account and checked my messages. She found out that I wrote like 2 months ago to a friend of mine, a girl. Message was "I've always wanted to date a white girl. No reply, it might start fire if my gf found out" (I'm an asian). And I was totally joking, it was a meaningless message, because we were chatting about those stuffs.

She broke me up but I haven't agreed yet, I love her so much and I couldn't stand my days without her. I'm still striving to get her back and she keeps rejecting me. I told her that I have totally changed since we almost break up last month, but she just won't believe me. I swear I love her so much.

What should I do?