Okay so I need some advice ladies.

I usually start my period late in the month. Like in the 20s(and I'm talking about September). I wanna say sometime between 17th-20th(I can't remember which day it was) I had this bad uterus pain. It didn't feel like cramps, I kno what those feel like. But shortly after I went to use the restroom nd I had a spot of blood on the toilet paper(not blood blood, more like that pinky/brownish color) so I thought I was gonna start soon, which I didn't. So on the 22nd I went nd bought 4 pregnancy test. I took one that Tuesday afternoon nd it was negative. Then took the other 3 the rest of the week on each morning. They were all negative. If I could be POSSIBLY pregnant, (now that I think about it now) do y'all think those days I took em was too early? Its October 4th now nd I still haven't started. Also my back was hurting on the 1st, like when you're pmsing. So do y'all think I could be pregnant? Should I even bother to take another test? Or do y'all think my period just bein weird?