Hey, sweetie, creampuff, sugarpie, other edible things, I'm gonna give you the best advice I can give you atm: People come and go, and I know it's hard when people leave but hey you should be happy about the time that you spent with them, you can be sad about them leaving too, but just remember that you can probably survive without them. If your friend is hanging out with someone who picks on you, tell them that they pick on you and that you don't appreciat them hanging out with the person. No one is watching/looking at you, and if they are they're probably checking you out. Also if you want to beat insecurity/feel more confident, do what I did and stand in front of the mirror EVERY MORNING and say something nice to yourself. Beating insecurity is hard but complimenting yourself is huge help.