implantation bleeding? pregnancy symptoms

I took an opk the day my husband and I had unprotected sex. It tested high. Days later I had swollen breasts that felt like they didn't fit in my bra, and were so sensitive, and still are. Now AF is five days away and I have a brown discharge, and very slight spotting since yesterday that ranged from brown to black and a very small amount of red. It's too soon to test according to glow and every test I've taken has been negative thus far because I can't stop thinking about it. Did anyone have similar symptoms when they were pregnant. I have this feeling like this isn't our month since my cramps feel similar to PMS.