What is this?

Im sorry is this is in the wrong group. I don''t know what this is? Uterine lining or possible miscarriage?

I recently started seeing my most recent partner again in September of last year. It's been mostly blowjobs and anal. I got back on the depo shot on January 9th. We had sex early morning January 25th (well past the 1 week window for the shot to take full effect and the only time he has finished inside) and haven't been able to see each other since then. I had very light spotting on Monday (just barely a pink tinge on the toilet paper), a light what I thought was period yesterday (barely had to change pads all day) and light bleeding today with very mild cramping on the left side, just barely able to feel it but enough to notice and only lasted a few minutes. I've been on the shot a couple different times before and my cycles are different each time so I figured that's what this was. I saw this just now (around 8pm) in my underwear when I went to the bathroom. I've never had uterine shedding in my underwear before (I'm 32) so I'm not sure what it looks like. Is that what this is? Also my emotions have been haywire all week; upset and angry and depressed as well as exhausted that I chalked it all up to period symptoms.