Is it normal if i'm always being teased and made fun of?

Its okay if you have like one person who does that, who jokes around with you about you, teases you, blah blah. But when there's a lot its like am I make-fun-able? I don't understand. And the worst thing is I have these confusing thoughts in my head that conflict with each other based on what I have heard. You know when they say someone likes you they joke on you a lot? So sometimes I feel that way about the certain people who do that to me. One of them is a girlfriend of mine and she even said straight up after I confronted her about it that she does that to people she is comfortable with. So I don't know if I should accept it because I cannot deal with it 24/7. THEN there are these two guys that get on my effin nerves and I have already imagined myself literally shooting one of them because I want him out of my life as if he never knew me or something. But those two guys are always messing with me and its like non f*cken stop like why !?!?!?!?!?!?! STOP! However, its not like a "hate" thing its like they are "friends/acquaintances" but they're always bugging me which is why I feel like they maybe do like me. And if I mention that to them, they will laugh their ass*s off because again, they like to mess with me (btw they don't know each other). I already kind of confronted one playing around ish saying he likes me and like I said, he's like "what hell no, blah blah." If I mention it to the other tho I swear he will humiliate me.
It is such a confusing subject and I can't stand it. It might not be a big deal in general but it is to me. I like knowing what people are thinking and figuring them out so when I don't have a definite answer because of how they act towards me, I go crazy. I don't know if I should keep them in my life or shoot them and eliminate them forever like we never met. I'd go with the ladder but meh. So if its not because they like me, then why don't they just leave me alone if they're gonna be mean to me? I already had it with one of them cause I know him longer so I told him when you're ready to be real and not just mess with me all the time, come talk to me but for now its see you later. I am about to tell the other guy the same too except he's a little less likely to be a friend in the future. I really don't like him so once I confront him depending on how it goes, I will probably delete him out of my life, like blocking him out on facebook, forever. Sorry its an essay but I really needed to vent and I need some answers. Do people who like you tend to mess with you all the time? and is it normal to always be teased? what do I do with these douches? and I'm not just talking about my girlfriend and those two guys. SIGH........