Pregnant or not?

Ca

I've been feeling off lately. I noticed my stomach getting bigger and getting stretch marks but I'm not gaining weight. My boobs have been sore on and off and getting bigger as well. my nipple rings have been giving me some trouble too. But I've had them done for over a year now with no problems. My period was late by 4 days but on day 2 of it being late I noticed when I wiped it was a strange brown/greenish mucus. And same with Day 3. On day 4 of being late it seems like I got my period but it's really different from other periods. When I first realized I had gotten it it was really clotty dark brown and red. But now there's no clots and it's mainly brown. Usually when I get my period it's heavy and pretty thick and bright red until like the last day then it's either light pink or brown. I've already taken 2 pregnancy tests. Both seem to be negative. I took one acouple days before my missed period and one on day 4 of my missed period. Any advice?