Bf didn’t defend me?

This morning we took the train together. It was very packed and 2 females for no reason started purposely pushing me and giving me dirty stares for no reason. I had my bag over my shoulder and I pulled it away from the girl and she started to push me. He looked over at me like I did something wrong, shaked his head and told me “you’re on your own” am I wrong for being upset at him over this? I feel like he should back me up and protect me when it’s needed. So basically if these girls would of jumped me I would’ve been on my own.