NeuroTalk Support Groups - Help: Is this a concussion? Doctors perplexed!

I sustained a VERY mild head injury on May 30th. I slipped and fell backwards on the sidewalk. The impact was not terrible though, because I fell on my butt first. I didn't black out or anything. I didn't even feel any pain (although I was drunk.) Later the next day, I noticed intense spaciness/feeling in a dream, fatigue, and this feeling of intense overload in my brain when I worked. Taking lots of rest, I felt almost fully improved after two weeks and began to return to a more active lifestyle (although no drinking/smoking/etc.) For about a week, I was fine, but then I woke up suddenly with intense fatigue, sleeping up to 16 hours a day. The spaciness/feeling of being in a dream returned too.

It's been 10 weeks now, and I've seen minimum improvement since my relapse. I sleep less but still face fatigue that comes and goes and constant spaciness. I've had an MRI, Catscan, cognitive testing/neuropsych, vision checkups, and a standard blood test (not extensive) and all come back normal.

Although where I hit my head sometimes feels weird, I've never had headaches, sensitivity to light, or any of the other more "traditional" symptoms. Is it possible I had a mild concussion but now am experiencing something entirely different? I'm very frustrated. I've had to quit all my summer jobs and am supposed to go back to college this fall.