Spotting to bleeding - any similar experience?

Kendall

I’m 11 DPO and for the past week or so I’ve had a ton of cramping and my uterus has felt heavy. Yesterday I had some brown spotting and it stopped. This morning I had bright red blood and put a tampon in assuming my period came early. But when i took my tampon out later, it was dry with some light brown spotting. What could be going on?! I’ve been testing and all very negative :(