Regrets about high school? advice?

My high school career is over in a month. I made no new friends.. had no fun times. Nothing really. I was just a loner for the most part. I'm just sad because i've struggled with social anxiety all through and just havent made the most of it. I'm more depressed because it also concludes my childhood. I'm 18 now and I really miss being a kid. My passion for playing outside at recess will never fade and I still ask my mom for that new video game. I will never have a successful future because of my neurological disorder. Its just been a very hard phase im going through and its really difficult to accept. I just want to be young and do the kid things that I enjoy doing forever.