I feel lonely, what do i do?

[...yo]

Im a guy, 15 years old, and i feel really crappy. I'm sitting here, watching the Super Bowl alone. I'm just texting one girl and a guy i know.
Let me go back a little. When i was younger, like between 5 and 10 years old, i had skin problems (eczema). It hurt me emotionally. People would always ask why my hand looks weird and why i have cuts on my face. I was really shy and insecure about myself when i was young, but i was still an optimistic child, hoping i'd get better one day. My life, personally and socially (at school) was rough and painful to remember. I grew up really bad an gave up on my faith in religion and stuff when i was 11 years old. In 5th grade, i made a lot of friends. When i graduated i was hoping to move onto the middle school nearby with my friends but my parents transferred me to another area of my state. My life sort of reset and i knew nobody at all at my middle school. I was shy for the first 4 months of school. I made friends with these 3 guys, and met their friends and met some girls too. I was in love with this one girl but she didn't want a relationship so i just kept flirting with her (my eczema got way better after 5th grade). In 7th grade i knew many people, and in 8th i basically knew the whole school. I graduated, and am now in a high school that's pretty good, but not many kids from either my elementary and middle school go to. I feel alone here. I only know like 50 people and most of them are guys. The girl i loved goes to another school and i still have feelings for her but don't have her number. I feel like i've lost all confidence in myself, i feel a little but not a lot insecure. I'm also shy again.
Due to how i grew up, i don't use any social networking sites. I feel like i ruined my life by not using it in the 7th grade when my life turned around for the better. I made a facebook, but was too shy to put up a profile picture of me so i never added people on it. I still have nobody or anything on my facebook. I'm worried that i'll only have like 100-200 friends on facebook while all of my friends (who are outgoing people) have 700 to 2,000 friends and that they'll think i'm a loser.
The people i'm texting are talking about people going crazy on facebook and instagram and i feel depressed when i hear stuff like that because i don't use either and i feel bad...
I barely talk to my old friends. Recently every weekend i've been playing a video game called call of duty, on playstation 3, and my best friends from middle school go on too and i've sort of reconnected with them. It's the only time i felt happy in 2 years. They missed me too.

I wish i could just feel confident to add people, even friends who i didn't know well, on facebook. Then make a twitter and follow celebrities and stuff like that. And instagram to see cool pictures. But i'm so shy and worried to do it. I don't want to end up with a little amount of friends and then feel embarrassed. I don't even make a big deal of my birthday because nobody knows what it is cause i don't use any social things for them to know. I really hate my life, help me? What do i do? I dress well and everything and i'm not insecure about my skin cause it's normal now but i just can't get myself to make a facebook and instagram and anything to just have my life back. I miss being happy. My brother tells me im a loser cause all i do is play video games and that i have no friends but i do..