4 months late...

I am 4 months late, and have taken several tests and they ALL came out negative. I am freaked out because I want to start a family, I haven't gone to the Dr or anything. I'm scared he/she will tell me I can't have kids. I THINK I am getting SOME pregnancy symptoms, but what do I know? I have never been pregnant before. Someone please help me. I need advice.

p.s: Back pains, and mood swings