I find out that I had used the credit card my girlfriend reported stolen.
Oh no. Did you steal the credit card?
Yes, she didn't trust me, now I don't trust her.
You should not steal your girlfriends credit card. It is a crime to buy items with other peoples money with out them knowing. You should return the item back so you do not get in trouble.
Trust comes hard when you find your partner is a lying bitch.
I think it's best to take a breath and curb all the frustration before proceeding on where to go on. If you stole it, don't you think it was fair for her to report that? How about just being honest and giving it back so she won't worry anymore.