men are never interested in me

I had an online date cancel on me this morning and it made me realise men never seem to be interested in me. I struggle to get men to chat online and in real life I never get approached. my friends tell me guys look at me but they never come over. my last dating experiences have included one guy who seemed interested and then got back with his ex while dating me and then the last 2 guys I've made plans with have cancelled. I just dont know what I am doing wrong.