Totally confused!!

Hi,

Every since I had unprotected sex on Jan. 17th, I've been having symptoms of pregnancy, but I took three pregnancy tests (the last was at the doctor) and all three came out negative. On Jan. 17th i had sex-on jan.24th i had a 4 day period that did have regular bleeding and cramps. i had sex again on feb.19th, and my period came on on feb.22nd. It wasn't really like a period because it was just spotting and light bleeding that was pink instead of red. it lasted for five days. Before that though, i had cramps and no blood. Now, my nipples are extremely sensitive and the left one hurts dang near all the time. the right one is less active, but it throbs every now and then. my hunger is out of control and my attitudes are things that i question now-a-days.

So, here's my question. Is there a chance my pg tests could've been wrong, or is it that I'm just now getting pg and having signs, or is it plainly something different. I'm a young girl, not even 18, and I really need to know what's going on with my body and my bf too. We need to know now, so that we can plan ahead, but I don't wanna move forward on a false alarm.

I feel like I have to vomit and nothing comes up, and i have headaches out of this world. My fatigue is so not normal and my feet and back hurt more often than they should! And will someon please tell me how to stop my left nipple from hurting and throbbing in pain! I haven't even touched them and they're overly sensitive! My stomach also feels funny from time to time, like one minute it's tight and the next minute it's soft-but it's tight or hard most of the time, and if you push inside the middle with the palm of your hand, it hurts a whole a little and feels funny.

any info would be lovely and very much appreciated.