Oh I feel your pain, my MIL is the same way, and it SO frustrating!! What does your husband say about it? Whenever mine pulls this kind of stuff, he is usually supportive and sticks up for me. Having him on my side makes it much easier to say no and set boundaries. That's a hard thing to do though, and if you're husband doesn't want to contest his mom, it's even harder. When situations some up like this, stay calm. It's hard to do, but it's really important. Tell her you can't do it, because she didn't give you enough notice, and you have plans. Then really have plans, so you won't feel guilty those dates, you'll be too busy having fun. Or, confront her, tell her you don't like the way she is treating you, and as her DIL, you deserve the same kind of respect. This is really hard, and I repeat it to my MIL often. She doesn't always get the point (usually she doesn't) but she'll at least back down from this round. Keep at it, eventually she'll understand you're her equal, not her servant. Good luck!!