Man, homey, you've got it bad. Your own family doubts you? Ouch!
I would highly recommend you go buy a standard social skills book; not one about gaming. Learn the fundamentals of giving a good impression. I would personally recommend "First Impressions: What You Don't Know About How Others See You" by Ann Demarais, Ph.D. & Valerie White, Ph.D.
I was a psychology major, and I'm familiar with a lot of the concepts they talk about. They use proven studies to back up their arguments. Check it out.
I could be a complete loner (which I have been - trying to get into grad school

), and people still find me to be friendly and charismatic from the get-go. Here are some basics, so you can have the same effect:
1) Have good posture - shoulders back, back straight, and head faced forward. Your posture says a lot about you. The more you hunch or stare at the ground, the lower perceived social status you send to others.
2) Smile - smiling is HUGE. Don't have a stupid grin on your face, but practice always having a small smirk. A smirk is a very cocky smile, and gives you an air of confidence. Have this ALWAYS.
When you are going to smile, give people a "slow smile." A quick smile is that grin you flash at random strangers. Slow it down just a tad, and it look more credible to people.
3) Whenever you're next to someone you don't know (that's not part of your set), take the initiative to introduce yourself. This establishes your status as a dominant type. Even if the set isn't
your set, you're essentially welcoming the stranger. This shows others that you're not shaken or deterred by unfamiliarity. Girls respond to this very well.
4) Dress fashionably - you can't expect people to respect you, unless you dress as someone who demands respect. I'm not saying you should go to school in an Armani suit, but wear clothing that shows others you're confident in your body. Try to dress trendy, but with your own sense of style.
5) Lift weights - You'll look better, feel better, and it'll do wonders for your confidence. Frankly, I don't see a reason why you shouldn't lift weights. If you get that chiseled physique half your work will be done. Looks aren't all important, but that doesn't mean girls are blind.
6) Treat everyone the same, regardless of status or age - I treat everyone I meet exactly the same. Old people, young people, wealthy people - it doesn't matter. I'm polite and respectful, but I don't ever try to kiss up to anyone. By showing everyone that I don't care about status, it elevates my own status. I appear as a natural leader. Make sure you've got some decent social skills and charisma before trying this, otherwise you'll just look like a disrespectful ass.
7) Have some interesting stories - look back on your life, and pick out things you find interesting. Every socially adept person knows how to small-talk and elevate a conversation. You need to be able to be able to talk about light subject matter, and be able to transition into more deeper subjects smoothly. Also look up some news stories online before you go to any social event. You NEED to have interesting things to say.

Know how to listen - Lots of people make the mistake of talking too much. They think they're being interesting, when they're really just coming off as annoying. Girls HATE guys who drone on and on. Know how to focus the conversation back to the person. Believe me, it makes your gaming easier, since the girl will be basically feeding you information you can work with. Also, she'll naturally feel closer to you as she continues to self-disclose. This is also useful if you're running low on #7.
9) Acknowledge everyone in the group - You're an alpha male, so act like one. It's your duty to welcome everyone into the fold. Do it tactfully, but make sure to do it. If your friend brought someone you don't know, ask him to introduce you two.
10) Learn to lie well - It's an ugly thing to say, but you need to learn to lie. Sometimes, people are going to say something positive or stupid about themselves, and you have to be able to agree with them. Avoid making any shifty eye movements, don't ever cover your face with your hands, have a nice smile, and nod along with them. Every socially adept person knows how to lie well (and a PUA does, too).
I could go on, but I hope you get the basic idea. Just be friendly and act confident. Things will start popping for you eventually. Some of your classmates might start talking smack, saying that you're trying to be someone else. Believe me, that period will go by quick. In Freshman and Sophomore year in high school, I was a huge nerd. I couldn't get a date even if my life depended on it. Junior and Senior year, I was one of the most popular kids in school. Nothing about me changed - just my mentality.
Peace.