Hi I Am 21 Years Old Have Been Trying To

Hi i am 21 years old have been trying to get pregnant but had no luck as yet. I had my menstruel cycle recently blood was thinner and lighter, and at the end verry dark? And about a week after that also started feeling like something is pulling from my belly button down and feeling as thow its tightening... And i just starter getting a clear discharge from my nipples. Feel erritated all the time and sleepy... Went for a back massage with my husband and got cramps almost like hunger cramps and movement in my tummy. Can this be early signs of pregnancy? Pregnancy test showes neg so far. Should i be worried? I am also RH O- and anemic already lost a babby dont want that to happen again. Pls help