My boyfriend is mad at me

He’s mad at me because we were out at a Halloween store and I was going to get a costume but I put it back and I told him it was because it probably won’t look good on me(because im really self conscious and have body image issues) and he just got pissed off and when we got to the truck he kinda went off on me saying he’s tired of me being so negative and tired of my pessimistic attitude all the time......