Maybe I overdid it.
Week 1: 100 miles. I've run 100+ mile weeks before. Not a ton of times, but I have. I don't know if I've done as many short, semi-fast 6 mile runs as I did. Over Spring Break, I tried to meet with anyone on the team who wanted to run whenever they could do it. That sometimes meant 3 runs a day. Luckily, I did not repeat the 16x400 workout! It was a lot for the week.
Week 2: Fewer miles, but some hard running. This week I got 15 hours of sleep in a 5 day period. I tried to sleep more but couldn't. Could be a sign of overtraining now that I think about it.
Week 3: Worst cold/flu/bronchitis I can remember ever having. Completely shut me down. I only got in 12 miles for the week. 9 days later, I've been running but still sick.
I think it's safe to say these could all be connected. Sometimes, I guess, too much is too much.