TMI Help, how do I tell my OB what this is?

So this morning we had sex and when he was into it hurt a little, but I just left it at that because it was almost finished.

After my significant other said I felt looser and low key ticked me off but then I went to the bathroom and I wiped and the TP was a brownish color and I put my fingers up to investigate and I got this out? This was the only thing up there.

How do I even describe this to my OB over the phone? Anyone have any experiences to set my mind at ease or warn me?

It’s been a really tough pregnancy and I’m only 17 + 4, I feel like I’m not catching breaks and I’m just terrified.