What Causes Pain In The Lower Abdomen After Walking?

I have had pelvic/lower abdominal pain for two days now- it seems to worsen after walking a good distance, physical activity, etc. The pain is severe at times, and has caused me to be nauseous & have a very decreased appetite. I also fee kind of foggy , but haven t rested well either. I do have a hx of kidney stones, and am terrified. Two years ago, I had to have a 4mm stuck in my UPJ extracted & a stent placed. After stent removal, I had multi-organ sepsis, and was hospitalized for 12 days- super sick. I again had another one in 2014 when I was pregnant with my youngest- but this one ever passed, it was 7mm. I often have pain in one or both my flank areas, but not typically consistent. I drink plenty of water & attempt to get decent exercise per week. Over the past couple days, my pain has slightly mimicked a stone, but this time my pain is intermittent in my flank region, and is not severe. However, I have intermittently severe pain & constant pressure/fullness on the lower pelvic area, right around (above & below- all around that area) my csection scar. I dipped my urine & only have a small trace of blood- all else appears to be WNL, but I did take AZO with the pyridium-like medication within it. At this point, I m uncertain if it is urological/nephro, or ob/gyn. In addition to this odd findings, I wiped tonight & there was a mucus clot on the tissue- much like I passed when I was pregnant & passing a mucus plug. No odor, no notable discoloration (slightly pink in nature- but likely from the medication), no gross blood, and haven t had any since. Please advise on your thoughts, as I truly am at a loss! Thanks so much!