Whats going on if i have pregnancy symptoms yet no positive in a home pregnancy test?

Hi. My name is Tiffany, i am 20 years old and I have a few concerns with in myself that I hope you will be able to help me figure out. I use to have a really regular period that was heavy and lasted 7-8 days but as of February I was 2 weeks late and when I did get it, it was really light and only lasted 3 days. Since then I have had a light period every month around the same time but from early march I've been tired all the time and for a while I felt sick with certain foods, get hiccups from time to time and have had a few sytmpoms related to pregnancy. I have taken about 16-20 home pregnancy test and all have come out negative the most recent this morning and I have had two blood test and a urine test done a few months ago at the planned parenthood. I am sexually active and did have both unprotected and protected sex. I was a pretty thin person around february but as of lately i have gotten a bit of a belly and family members have
contiunely asked me if i was expecting and my answer is no because of the negatives. Can there be something wrong with me?