Ask your doctor for a CT SCAN or ask him or her to check your urine too.My doc saw that I had a bacterial infection in my intestines and I had also an infection in my urine. But what helped me the most was the test also showed that I was backed up in my digestive system. I had BM in my colon that hadn't come out.
I have problems with constipation and when I can't go it caues problems in my appendix. He gave me 2 types of antibiotics and some Miralax and I feel so much better.I know the one for the intesine bacteria was Metronidazole 500mg.You can also get it online without a prescription. The other med for the urine infection was called Nitrofurantoin Mono-MCR
I'm not saying this is your problem but if they aren't helping you go to another doc. Because I let my doc know that sometimes I would smell like rotten eggs after eating certain foods. But a few times I was able to smell a fecal smell too. I should mention that I also take probiotics as well.