95 Impreza 2.2 with a 134a system if that matters. Most of the time the AC works really well (although it drags the engine down noticeably). Occasionally the compressor will start cycling on for a second or less then off, repeating every second or two an a really regular pattern. Cooling goes from working great to non existent when this happens. If I turn it off for a few minutes it will usually start working again. What would cause this?

prolly little low on 134a refrigerant.

It is VERY cold though when it works... Also I just realized I added a 14oz can about 2 months ago and the issue started about a month ago... is it possible that maybe I have too much coolant instead of not enough? I dont completely trust the cheap gauge I have, and I couldnt find a sight glass to check for bubbles.

Very strong possibility you put too much in it. Quit using it and take it to a place that works on A/C and have them get the level right.