Am I allowed to be mad?

N🌻
So my so mum takes my clothes when I'm over and washes them without asking me. While my so was doing some driving practise with his dad and me in the car she took my clothes out of my bag and washed them. Didn't tell me either or ask. I cleaned them the day prior and hadn't even worn them. Now I'm going to a party and my outfit is at their house still because she took it and washed it. 
I get it's nice and all but I wasn't even told or asked. I didn't think to check my bag since I left it all in there. 
I'm too far away to turn back and get the clothes and I won't get them until next weekend. 
Am I allowed to be mad at her for taking them and not even letting me know, or should I just be grateful?