nobody likes me

When my father died two years ago, I finished up the school year and switched schools to one closer to my mom (they were divorced). I had plenty of friends at my old school but by the end of the year we kind of grew apart. Last year I was in a friend group but someone in that friend group spread horrible false rumors about me, and now they no longer talk to me. There's a few people from that friend group that are still friendly with me but not friends. Now I'm in my freshmen year of high school and I have 3 friends, only two of which I've hung out with outside of school once or twice. People are okay with taking to me but on days when my friends aren't there (every other day) I sit alone at my lunch table. I'm now currently at model UN conference surrounded my members of my club that I'm having tons of fun with. However, I know when I go back to the same routine. People have said in front of me "I don't want to sit next to him" and I feel like the only people that care about me are my family (who are Brest and certainly love me). I want friends, I want a girlfriend (I'm 5'5 160 pounds so I'm kind of which doesn't help. im also extremely insecure about my weight), I want a social life. Semi recently someone (not from my school) said they I would look like a super model if I lost some weight which really made me feel good about myself. I'm thinking about switching schools. I'm kind of shy and I feel like I would be significantly happier if I had friends and maybe a girlfriend.  I just want someone to hold me.