I get called camp/gay

I've started university, I'm 20 years old and I get called gay/camp sometimes. At the beginning it didn't bother me but when a good 2 or so girls say it per week, it kind of started eating away at me. I've got absolutely nothing wrong with gay people its just I'm not gay. I'm 100% straight. Its obviously something about me that makes them think that though. I think its the way I act however I don't really notice it. Maybe the way I walk or something I don't know.
Its just my confidence is getting pushed further and further down every time some says it. I still go out and pull people but I'm not taking anyone home or anything. I've noticed I've been less confident when going up to girls in clubs.
My question is basically. How do I keep myself strong emotionally because at the moment I'm literally on the brink of crying which is really unlike me. I'm just finding it so hard to ignore at the moment and probably the main reason is because I really want a girlfriend at the moment. Usually I'm ok with taking "banter" but I realised this is more than that and it actually hurts emotionally.