Really strange stool for past few days - wrinkly and elastic

Hi,

24/male/no other major health problems.

I've had very mild intestinal discomfort for over a week, not really pain but a feeling in my lower central abdomen like trapped gas or some kind of stitch. The past few days, though, I've had a change in bowel habits to accompany this. I've had wrinkly, prune-shaped pieces of stool that have a fleshy consistency, almost like meat, and are connected together by some kind of strong elastic central cord. You can pull the stool out like an accordion and it will still somewhat snap back to its original shape. No visible blood, and only one day there's been a tiny bit of mucus. I hadn't made any changes to my regular eating habits when this began.

I went to a physician, showed him a sample, described my symptoms, he palpated my abdomen, and all he recommended was to take fiber and probiotics. He didn't think it was anything serious like cancer or IBS, but I've been following orders for nearly a week and I haven't seen any kind of change in my stool. No matter what I eat and even with the fiber and probiotics, it's still the same coming out, lots of prune-like pieces bound together by a stretchy string. Today I passed one very large one and a few that were long and narrow. They all floated, which this stool normally doesn't do.

I want to trust my doctor, but I'm worried about these symptoms continuing with no change. I'm probably extra nervous because my mother has colon cancer and I've seen how much she's suffered, but this is the strangest stool I've ever had and just not normal for me at all.

All advice is really, really greatly appreciated. Thank you all so much.