Hi there
Good on you for deleting your FB account. I have done the same for that reason.
It can be hard not to compare ourselves to others, but we don't know what goes on behind closed doors. I was beating myself up for not having a relationship and then I hear a lot about people who are married or in relationships and unhappy, so now I feel lucky to have my own freedom.
It can be hard to focus on the positives, but I have written a list of my good qualities and try to focus on them. Maybe stick them up on your mirror so that you see them every day to remind yourself that you are good enough just as you are.
Take care