I'm a little late and haven't read all of the responses.
Yes, OT is real as I dealt with it really really badly. From the time I went from too much training (overreaching) to noticeable recovery from my overtraining symptoms, was almost 18 months.
I was a runner, ran too too much, too many races, etc. I literally ran until my quads were sore for over a year straight, even after being forced to stop running. My sleep was the worse ever, appetite screwed up, apathy, depression, all kinds of stuff l. It was a dark time, I couldn't train at all, sleep, nothing helped. I went to all kinds of doctors looking for what was going on and the only thing that helped was time and rest.
I know I'm susceptible to it again as I have the drive to push beyond my limits. Also lyle McDonald has an awesome 9 part series on OT and overreaching.