WHY AM I LATE!? PLEASE HELP IM SCARED

Im 20 years old i weigh 260 lbs and am 5'5'' (i know im overweight) i have a medium stress level and am not very active my period was really irregular in the past but in the last 5 months its been fairly regular (no more than a week late at most) my boyfriend and i have sex about once a week and we always use a condom (i know the proper way to use a condom and we always check for breaks or leaks afterwards and have never found any) i am about 2 weeks late i have taken an at home pregnancy test about a week ago and it said negative. I keep feeling like im PMSing and i have alot of discharge, more than usual, but still havent gotten my period. Could i be pregnant? What else could cause this? I love my boyfriend but i am young and not ready to have a baby and im very worried. Please comment any tips thoughts or advice you have.