Can I bail on my girlfriend last minute?
Is there a reason you don't want to go with her?
I'm just really upset right now and being around her is a bad idea when I feel like this.
Wanting to stay away from your partner because you're upset is understandable but if you made plans with her you shouldn't bail last minute. Just warn her you arent really feeling well and next time if this happens give her more of a warning.
Can't I bail on her?
Maybe you can adjust your plans to do some activity you will feel good doing so you can avoid bailing.