I've been fat all my life..,up until about august of last year...I worked my ass of and lost bodyfat and gained alot of muscle (granted I'm still a bit flabby)
I went from 5'10 240lbs to 6'1 183 lbs with 14% bodyfat

So yea a big transformation
The problem is I am still stuck with that fat boy mentality..I'm always self conscious about my appearance and I have low confidence socially...
But when I'm in a comfortable environment (friends party, school) I tend to be a bit more social when I have a friend around...but when I try and talk to a girl I fell retarded and akward ...
I play alot of videogames and have almost no social life, I have alot of friends but they are not "close friends"
I want to completely transform my social life, but I have no idea where to start...I've been reading some of the progress journals and they are really inspiring...please help me! I want my last 2 years of highschool to be remembered for the rest of my life!

Lets see some pics of you as you are right now. Facebook maybe?

Read Chapter 4 of The Lost Chapters Of The HighSchool Bible

It starts you off well, but you gotta get over the Taboo of saying hello to people. So do exactly that, say Hello TO EVERYBODY.

You stated all your problems yourself, I'll give you the solutions that you dont seem to want to touch upon.

You have 14% bodyfat. Do research and hit the gym 3-4x a week. Find a nice, low calorie diet and stay away from simple carbs. You've done it before, and this time, it's not as much to lose, and then you can start bulking up.
Being fat in highschool is not ideal. It's less ideal than being skinny.

You also want to change your self-image about this. Everything under 15% is acceptable, but like 6-8% and muscular is ideal I think.
Do not procrastinate everything else, just because you're not "Slim enough" or "Bulked up enough", that does NOT help.

It's mostly in your mind, as you said. You're just resisting change.

It's probably awkward because you feel its awkwards, and then she feels it. Force yourself to talk to more chicks, it's pretty much the only way.

I can highly identify with the videogame part. I used to be a "pro gamer" before I left norway. Ive almost quit gaming, and Ive started going out, that was simply 2 variables that needed to be changed.

You wanna transform your social life? Then be social. Thats it. Going out will really change you, just look at me after I started going out.
Going out and being social will solve a lot of your problems. There is almost a direct correlation between how much you go out and how much you improve and how many chicks you get.

You simply have to take charge of your own life Now.