Hi Cathy Jo
Your symptoms of left sided pain, fever and loose bms at four weeks post op raise a huge

for me.
When I was at 4 weeks post op, I developed the same symptoms. The pain was a stabbing pain in the lower left side of my abdomen. Sometimes it felt like it went closer to the groin area but mostly it was over in the left side closer to my hip bone. It felt like it was deep inside me, and it was way worse than any of the pain from my surgery. I had a low grade fever and then it started to spike a couple of times a day (typically morning and evening) up to 103 or 103.5. Loose bms too, and the pain would sometimes lessen when I had a bm. Does this sound familiar to you?
The first tests my DR ordered were blood work, urinalysis and an ultrasound. The blood work showed an elevated white count. The urinalysis showed a few blood cells but otherwise was OK. The reason for the ultrasound was that my DR suspected either a hematoma (big blood clot) or abscess around where my left ovary had been. The ultrasound showed nothing abnormal.
DR had the presence of mind to call a colleague who is a gastroenterologist. He told her to order a CAT scan with contrast, put me on a soft bland diet and get me on Cipro and Flagyl (2 powerful antibiotics) right away. Thank goodness he did! They couldn't do the CAT scan until 2 days later, and the pain was awful and fevers continued during that time even though I was already on the antibiotics. It got pretty scary there.
The CAT scan showed diverticulitis peritonitis.... the walls of my colon in the area of the diverticulae had thinned so much the infection was starting to leak out into my abdomen and spread. That's why it took so long for the antibiotics to start working. A day or two later I started to feel better, and then went in to see the gastro doc.
To make a long story short, I was on those 2 antibiotics for a total of 30 days before it finally got rid of all the infection. Had to have a colonoscopy and a barium enema to give them a look at what kind of damage there'd been. I have to watch my diet now (no nuts or seeds) and wait ... if it comes back I will have to have a colon resection to avoid the possibility that it could rupture.
I'm not telling you this to scare you or because I'm sure you have the same thing I had... just to let you know it could be serious and to make sure your DR doesn't treat it lightly.
If your ultrasound shows blood clots then the treatment may just be to give you blood thinners and keep an eye on you. Given that you have a fever though I'm inclined to favor the idea of some kind of infection, either abscess or diverticulitis. Please keep a close watch on your temperature, and make sure your DR follows up. I don't want to think of you having this go over the long weekend... please, if your fever goes up around 101.5 to 103.5, either make sure the DR sees you or go to the ER, even if it's over the weekend.
Good luck, and please let us know what you find out and how you're doing.

s,
-Linda