You need to see a doctor and probably get on antibiotics. I understand that you don't want to go to the ER, but if your doctor isn't available until Thursday, you need to see someone. When you called your GI did you tell them you think you have an infection? That's what it sounds like. Maybe call them back tomorrow morning and tell them that and if that doesn't work ask them to call ahead to the ER or urgent care because you have to see someone. At my hospital there's usually a resident GI or internist on call, if they don't know what to do, they contact my doctor.
I'm not sure what kind of complications something like this could cause, but I know I'd be nervous and want someone to look at it sooner rather than later.
49 years old, Crohn's Disease
Six resection surgeries, permanent ostomy, adverse reactions to Remicade, back on 6MP for maintenance, hoping for a long remission from this last surgery.