First, don't throw away even potential friendships. You could tell them you got lost or something
This is the main thing tho:
Instead of focusing on finding a girl, focus on making friends. This can include guys or girls, but just focus on finding people you can hang out with, go out with (even if you cant drink), and can talk to. Talking is very important, learn the art of small talk
(girls love to talk about themselves, you can usually get them talking and just ask follow up questions for hours hehe) Once you find yourself with a good group of friends, branch out, you can probably find a girl from them.
As for good places to find these people, I tend to agree with the above post concerning moving out of the house, or getting a part time job.. plenty of ideas here..
I feel for you man, and good luck. Youre not the only one with these types of problems.