How do I let go of peoples actions toward me?

I don't have much in life and I have a severe lack of self esteem due to alopecia that destroyed my life. Recently I had to attend a wedding along side my grandpa and we were just invited out of formality because the grandpa are siblings. I was invited because I need to take care of my grandpa and not because they actually like me. I don't have much money and had to take time off work to attend this wedding and so to purchase the outfit I had to go to a thrift store because I couldn't really afford anything but still wanted to be nice and dress respectful. The day of the wedding I got of my morning job and got home dressed and took my grandma to the hall where as soon as I entered get getting remarks about my clothing and also my biggest insecurity which is my hair and mocking me by telling me to ease off the drugs ( I don't do drugs). I was really hungry because I just got off work and had to head over and then a few people made the remark about me eating food saying " amazing how many people would travel long distance for free food" and "save some for the rest of us". Now I don't even want eat food because it keeps playing in my head. I don't why they just don't like me. I don't have anything and they still want to destroy me. I never said anything bad to them. It just hurts me knowing they just like to be mean to me and they know I cant do anything back.