Socializing suggestions + girlfriend stuff

Hey,

I have this problem and I need some advice or help or suggestions or whatever... - I'm a 19 year old male, get told I'm pretty attractive from time to time; but the thing is - I cant manage to get a steady girlfriend or even hook up with anybody at all... ever since I finished high school I've had trouble in the outside world (outside school-life) to find a proper girlfriend like the ones I had when I was in school. When I was in school I had at least 3 girlfriends a year (I know its not a very good thing because now all y'all are gonna think I cant keep a girlfriend for a long time lol) but anyway, and I had at least 7 girls in my friendship group at school with whom I hung out a lot during lunch break and stuff like that.

but ever since I left (its been about a year or so) I cant manage to find a proper girl on the outside world... I just dont know where to go to even find girls to flirt with... (I think im losing confidence on flirting with girls too... my self esteem has become a bit lower now that I've been alone for almost a year or so. its terrible...).

whenever I see my dad (he doesnt live with me so I only see him once in a while) he asks me "where do you hang out with your friends? you go to pubs and socialize with girls?" and I constantly tell him that I do go to pubs and clubs and stuff, but the truth is - I dont... I dont think I have much confidence to go to a pub or a bar by myself. (by the way, I pretty much dont even see any of my high school buddies anymore either... because we dont have a lot in common except for the fact that we were in the same class at school and happened to become "school buddies") but other than that, we're different people and I dont see anybody anymore, so I cant even go to pubs with MY FRIENDS because I dont have a lot. its tough.

anyone know how to help me with this? how can I get a higher self esteem and just go out there and how can I get to meet girls on the outside world? PLEASE HELP!