help??

So my period is/was 5 days late. I'm really confused because I'm spotting, my periods are usually regular and extremely heavy. I've been spotting for 2 days & I had wiped and I had little blood clots & then it looked like bloody discharges & kinda stringy. I had sex 3 times in my fertile window, but I'm having negative pregnancy tests, although I only tried a cheap kind. Should I test with a FRER tomorrow or should I just let my body figure it out?