Is it my fault?

My boyfriend and I planned to have a date to panda and i was ready for our date and stuff but he sent me a pic of a chat with his friends where he asked his friend if he wanted to hang out later tonight, I felt bad and i told we can go on Monday instead for our 1month being together so he can go with his friends and he asked me if i felt like he let me down, i was being honest i said yes and he got mad, we argued and he ended up calling me a disappointment and that it was my fault we couldnt hang out today. I feel hurt atm.😔 So now im thinking if it was my fault or not😕