Well, I think I might have an answer, actually.
My home doctor took blood for a mono test, and we got the results today. Apparently, sometime between five years ago and yesterday, I have had mono. I don't have it anymore, but it's really possible that I had a weak strain of it maybe a month ago and I'm still on the recovery path.
So, way to go school health center. Like my dad said, you would think if a college student has symptoms of constant fatigue for the past few weeks, they would include a mono test.
Oh well, at least I finally have an idea.