Psychologically, I have been told that laughing at random times in this context is caused by the desire to prove to yourself you are becoming crazy, but that is from a small time doc I know. Not to say it discredits him, but he could be wrong.
Anyhow, it seems you, no offense, feel insecure. It's normal for males between 13 and 20 some odd.
It also sounds to me like you are trying to portray that you are feeling lonely (here come's a duh, mr obvious from readers of this post...).
My advice is to join clubs. I joined wrestling one year and my popularity shot through the roof. If that's what you want, then go for sports and never stop trying. It's hardly physique that carries your through most sports as much as it is fundamentals and technique.
You could try academics, which opens a smaller group of friends that I find I can be closer with and have more fun around. These people, in my region, just need a good push towards conversation and then it's good to go. I prefer this group.