Unless he seemed to be gasping and taking very frequent breaths of air from the surface, there probably isn't anything wrong with the water itself. They can hover around near the top in corners when they're just stressed as well.
If hes not gasping or anything, no need to disturb him with a water change for now....just keep to a regular schedule of at least a couple 50%s and one 100% water change a week to keep his water nice and clean.
Since you're not too sure about the full water chemistry(also if you're on city water sometimes the water companies change things up so there may be something in the water that wasn't there last time), might not hurt to pick up a small bottle of Seachem Prime water conditioner if you can. It'll instantly take care of more of the harmful stuff in your water then other conditioners, and for about 48 hours it will lock and detoxify ammonia if that just happens to be present in your water for any reason and its the only water conditioner I know if that will do that.
Ahh, well water! I love well water. No chlorine and generally not a big risk for ammonia(last I checked at least).
You can sometimes have a higher PH with well water though. I know mine on well water was like 7.9. If where you go to school runs on softer city water, that may have just been your problem this go around. You've got a hardly little guy it sounds like though, he'll be fine I'm sure.
Well water can have heavy metals though, and not as many conditioners as you might think treat for that. The only one I know of off the top of my head is Prime, but I think there is one other brand as well....
As an update, he seems to be pulling through. He was quiet for a couple of days and seemed to have perked up, but he didn't want to eat two days ago. I was worried, but yesterday and today he ate and he built a big bubble nest this morning. He seems to be better, keep your fingers crossed!