@amazingme That is definitely a problem with typing rather than talking.
The big thing is none of us are doctors and I see that you realize this. If you are afraid right now, at all, get thee to a hospital. If it gets worse… hospital ASAP. Doctor regardless.
One of the thing that bothers me about “butt piss” is someone with a blockage like @Judi says is people will experience very liquid stool as it goes around the blockage. The thing is I have never seen high volumes of liquid stool with a blockage and you DID take mag citrate. Blockages also do not happen in a matter of days. Still… it is something to think about. Oh, I have worked in the medical field for decades.
I have horrid IBS and one can get into a cycle of laxatives, anti-diarrhea meds, laxatives, anti-diarrhea meds, etc. IBS can also be extremely painful… first hand experience here. You mention the pain so I have to wonder.
With IBS and other things you have to find a balance.
One of the big things is that you have to rule out any serious causes and the best person to talk about that, handling IBS, or any other bowel issue is your doc.
It could be something minor or it could be a huge deal. As I said… doctor. :)