maybe I'm pregnant and don't know

so I'm actually 2 weeks late oh on my period. I have had spotting 3 days before my period was supposed to come on, now I'm just worried I think I might be pregnant.. also I have had cramps that felt like my period and muscle pains in my legs and my breasts and nipples just became sensitive to the touch about 3 days ago.. HELP.... I also have taken 3 pregnancy tests two First Response test both came back negative and $1 test it came back negative also..