RV-12 pilot reported landing safely after experiencing a rough-running engine.

Narrative

Approximately 10 miles from the airport I experienced a very rough running engine. This improved by powering back and I still had full power. I entered the pattern and as I was about to turn from base to final I saw another aircraft on final so broke off to my right with the intention of flying diagonally away from final; away from traffic and reentering the pattern. When I added power the engine became extremely rough and I turned back toward the airport; concerned I would soon experience an engine failure; although still had power at the time. I thought I was outside of the traffic pattern at the time but when I turned back I saw that I was inside the downwind leg with two planes on downwind. I kept visual separation and announced on the radio that I had them in sight. I proceeded to fly past them; rejoin downwind; and land. The engine remained running.I recognize my decision making was very poor in this situation. My first error was not requesting assistance or at least announcing I was having engine trouble so the other traffic was aware of my situation. My engine continued to run rough and I briefly considered requesting assistance but since I still had power decided it wasn't yet needed (in retrospect; it was). Also; I did consider crossing to the upwind side of the runway but was concerned that traffic may have departed or someone could be going around and could create a further collision hazard. Overall; I panicked and made incorrect decisions.After landing and reaching out to a maintenance facility I contacted an instructor and discussed the situation I had just been in. I requested to schedule additional training on emergency procedures and discuss/practice situations with task saturation. This is something I will do on a regular basis moving forward.