Does this spund like an infection, uc or something else?

You won't know until your c-scope. Make sure the doc takes biopsies throughout your colon and hopefully the cecum and into Terminal ileum. Ask for a copy of the biopsies pathology report when it arrives. Hopefully, the doc will talk with you after the scope and give you a copy of the visual findings.

Welcome to the forum! When is your scope?

Please keep us updated.
q

Not necessarily, but it would be awesome if that was the issue.
Some of us have had initial infections, yet being the trigger for UC to be set in motion.

We've all been through the waiting game....not fun.

Make a list of questions you would like the doc to answer....

q

As the word "Chronic" is used then you definitely have a form of IBD, likely the Ulcerative Colitis with Proctitis as seen within your scope.

The wording on your biopsy report is consistent with what I and others with UC have in our biopsy reports. It's chronic, so they must have seen permanent cell architectural changes within your biopsy. You have active-inflammation, meaning your UC is flaring at the time of the biopsy. Diffuse means the active inflammation was spread over a wide area, an important finding pointing toward a a UC diagnosis (UC is never patchy with healed areas, inflammation, healed areas, etc). Biopsy reports always state colitis and sometimes say some of it looks chronic, and other newer bits look acute (infectious). Your report does not use the word 'acute' at all, so no worries of this being an infectious nature. It's a true IBD.

"Is this heading towards remission?"

Likely, you're doing well. Although I wouldn't declare a remission unless you have been symptom-free for a couple months.

"Is this a mild case?"

Likely. Mild cases generally have a better prognosis than Severe cases. However, UC prognosis is wildly unpredictable patient-to-patient, and Uc has a tendency to unpredictably spread in extent and severity, especially within the first 5 years of your diagnosis. So, there's no guarantees that you will always have a mild-mannered UC case with very few troubles. Just stay vigilant of your symptoms and tell your doctor should you regress/flareup again. Keep taking your pentasa when you feel well and when you feel badly as an insurance-policy to give your the best odds of not flaring up again soon and also your UC not spreading in extent or severity.