Hi, I'm Dr. Jill. How long ago was this first incident? Also, could you give me an idea of what specifically you are hoping to learn here?
It was only about 4 days before this one and I am trying to find out what could be causing him to be sick cause he don't want to eat and is lethargic and he drinks and he poops but has not peed for a day and a half
Well, what you describe would definitely be consistent with him being in discomfort. Unfortunately, this could be from many causes and may or may not be related to the previous incident. The fact that he's still pooping and drinking is great...might try some fruit juice to get some calories into him if he's unwilling to eat solid food. Any cough, nasal discharge, diarrhea, or fever you've noted? If you haven't taken his temperature yet, doing so may give some indication if there's in infectious process going on, though it is not completely specific for infection (increased temperature is a sign of inflammation which is often due to infection but can be due to other processes as well).
The lack of urination could be due to dehydration or a urinary tract blockage. Lack of urination for that long is definitely concerning. Is there any chance he's peeing when no one is watching, or is he down in the same place all the time?
Given how sick he sounds, I do think the best option would be a return to your regular veterinarian. He may need antibiotics for an infection, or a repeat of IV fluids if he's very dehydrated.