You're going have to continue to pursue what your diagnosis is from your doctor's office, ask for copies of your colonoscopy and biopsy reports. Ask at a follow up with your doctor, which you should have to explain your treatment.
Your doctor could've meant proctitis (just colitis), an infection, no worries, it'll clear up. He/she could've meant ulcerative proctitis, if so welcome to our elite club here
Ulcerative colitis is further identified by how far it goes, ulcerative proctitis is just the rectum, ulcerative proctosigmoiditis goes further, and pancolitis is involvement of the entire large intestine.