Am i pregnant,or am i just having a weird month?

so for the past weeks i've been feeling very nauseous,overly hungry,i get like small cramps,my back hurts from time to time,im usually always tired,about two weeks ago i would get headaches constantly, im pretty gassy(tmi i know sorry! :*D) My last period was on the 15th and i had unprotected sex like 3 times before and the day after my ovulation day on the 29th (the 28th being my ovulating day) my period was due on the 12th of this month and i guess i did get it, but it was brown w/ pinkish(hardly any) and it lasted for 2 days and i wore a pad but i ddnt even have to change it. Then it stopped for 1 day and then it was only there when i wiped. it never changed color except when the little pink rubbed off when i wiped.i've also recently been feeling somewhat bloated at night, and my breast are not too sore but if im leaning on a table or someone accidentally presses them they do hurt, but not like sensitive to the point where my bra hurts me. i took a pregnancy test about 1 week after i had sex and it came back negative. so what i was wondering, is that if maybe i AM pregnant and if i should take another pregnancy test?