I'm mad at my gf because she rescinded her offer to take us both on a vacation
Why did she change her mind?
Not sure, but I'm not very happy that she rescinded the offer without a proper excuse.
You're probably feeling very disappointed that you can't go on vacation now. Have you considered that maybe something changed financially for her and she can't afford to pay for it now? Maybe talk to her to find out the real reason and offer to pay for your half.
She can afford it but she still took it away. I just want to make her feel bad.
Well, there's got to be some reason. You should have an open talk with her about it. It's good to be honest instead of just wanting to make your partner feel bad whenever you feel bad.