Spotting.. help!!!!

12 days ago my boyfriend and I took a shower. He came on my lower stomach and I noticed it had dripped down to my vagina. I immediately started stressing out. 3-4 days later I started having sore boobs and constipation and slight cramping. My period is due in 4 days. I have been stressing and worrying myself sick over this. Sunday, 3 days ago, i took a pregnancy test. It was negative. I am taking another one tomorrow afternoon. My mother and i are on the same cycle. And this morning she started her period. I have had some light spotting this morning with slight cramping. I guess what i am wondering is if spotting a few days before your period is normal? My boobs hurt, I'm emotional, I'm bloated something awful, and I haven't used the restroom in a week. I'm so upset that I don't want to eat or drink. Could I be pregnant? My friends and boyfriend all think that I am okay and this is PMS. Are they right? Am I okay? Please help...