Weird period...

This cycle has been really really weird. I am usually extremely regular with cycles lasting 30 days +/- 1 day. This cycle was 40 days. I took a bunch of UPTs, all negative. Then I got my “period” but was super light and more like spotting because it was rusty colored. Right now I’m on cycle day 11 if you consider the first day of spotting day one. But I’m still spotting. Normally my period lasts four days with enough to change a tampon every six hours or so. I didn’t even need to put in a tampon this entire period because it was so light. I’ve continued to have light pinkish/ brown spotting but no cramping, just low back soreness. And I’ve taken a couple more UPTs and they’re all negative.

Thoughts?