Why do I care so much about how I girls think I look ? Why do I want girls to think I'm good looking ? Am I the only guy with this problem ?

I am 21 year old and work in office. I always want to impress girls with my looks . Everything I think of when I'm talking to them is if think I'm good looking. I also ask girls if I'm good looking . They say yes obviously because I don't think if you ask someone they will say no. One girls said I am good looking . Even though I think I'm good looking why don't I get the attention from girls that I think good looking guys should get ? I always look at other guys like actors and sports players that girls think are hot . I am also incredibly jealous when I see a girl talk to a guy. Yesterday I had a office party and I was getting very bored . I also realised that girls don't think I'm good looking because when I was sitting alone for sometime , literally no one came to me but towards the end two girls did . I don't drink and dont smoke and did not fit in at all and now my full weekend is ruined thinking whether girls think I'm good looking or not. I do see girls looking at me and they also make strong eye contact when I talk to them and so look at my beard or cheeks and they also look at me in the eye . How to know if they find me ugly ?