Symptoms depends where your inflamation is. If it is lower part of colon only, you may see only blood but stool can be formed. If your inflamation goes up more in left colon,transverse colon or right colon, you can have diarhea as colon can not absorb water from stool.
Best way to diagnose UC or Crohn's colitis, get colonoscopy with biopsy from each area. Sometimes colonoscopy visually looks ok but when they take biopsy, they can see colitis.
So rather than self diagnosing yourself, go get tested. First rule out any infecton with blood and stool test and then get colonscopy done.
And if it is UC or crohn's, like Doggiedo said each flare is different and you will be on some kind of medication. Hope this helps.