28 F Missed period, brown clump

TMI PIC IN COMMENTS FOR INVESTIGATION- WARNING

So I missed my period in March and April, and just got it this morning.

Since I was like 13 I’d been eating like total shit, all processed foods, fast foods, junk, candy, chocolate. Probably 95% of my diet. I’ve always been naturally “underweight” my whole life. However generally felt like shit because of my diet. I finally started getting into health stuff and have been eating better since just before I missed my period. I got diagnosed with a lung infection a few months ago, got given antibiotics, and then rediagnosed with the same lung infection (it never away) a week or so ago in emerg. They did a pregnancy test when I was there and it was negative.

for the past two weeks my boobs had been getting bigger and were horribly swollen and painful, but other than that I had no period symptoms. Last night I was woke up with the feeling of my nipples burning- which reminded me of when I got pregnant in 2019 and was about to lactate. (I did not do that this time, just a side note)

Instead, I woke up this morning with no pain and went to the bathroom and there was this goopy, slightly dried out clump on the toilet paper. It was dark dark brown, nearly black, and smelled like death. Not super strongly, but still awful.

I have also, at emerg when diagnosed with the lung infection the second time been tested for all std’s and it came back negative.

What the fuck has happened???