Hello
I'm in my last year of high school now. Last year was the worst year of my life - oneitis, family became really poor, my friends were complete d*cks to me. And as you guessed: I had no confidence, was rejected continually by the same girl who I was (am, but moved on) in love with... and I recognized my situation was self-perpetuating itself through my negative, needy, melancholic attitude - depression.
So I made the decision to make good friends, i.e. friends who'd be cooler, not be assholes to me or judge me, and who'd be more confident and laid back - qualities I wanted in myself. This began at the end of the year... and woohoo I have an entirely new group of friends and although I speak to some of them, I'll never return to my old group.
But here's my new issue, or sticking point if you will. They are hanging around the hot girls in my grade. They are friends with these girls, who I like (no crush in that group thank god) but I don't get along with them, and its mainly because of who I was last year and the bad experiences I had talking to some of them (like "Why are you talking to me

" and me interviewing them while they walk away)
Don't get me wrong, I think this is cool. It's just that it's out of my comfort zone, and I feel rejected by them before I even talk to them because old feelings come back. This is cancerous, because the state I'm in when they're around is of weakness and social awkwardness to the max. (It's not because they're hot, it's the negativity associated with them). Its deteriorating the few friendships I've made because I'm not the same guy when they're around.
Well, obviously, I need to let go of the past and loosen up. But its not going to happen right away.
And now for the final blow:
Tomorrow, those friends I mentioned,
won't be there. I am not, under any circumstances returning to my old friends who treat me badly. So I either get along with the girls and this goes away
or I die. Lol, not literally, but I'll be back to square one.
I am aware of all the positives in the situation.. and the negatives.. but anyway
My question is: How can I show girls who I've had bad times with in the past that I'm different, more confident and socially in tune, or that "I'm cool now"? In terms of body language especially, since I'm not in state when they're there. I just want to be friends with them, nothing more. From a lower level, what should one be focusing on in such a situation?