Overtraining Syndrome - Can anyone relate?

It's been three months since I last did a workout. For around six months, I was working out while underweight and so, not giving my body the fuel it needed to repair itself. Now, my muscles are weak and my heart rate is so elevated that after attempting even a 10 minute warm up, it will still be high when I go to sleep. What's more, any kind of exercise turns me into the Grinch - it's like 24/7 PMS! I'm already in touch with my doctor and will soon be seeing an exercise physiologist. I just want to know, is there anyone out there who has/has had the same experience? I would love to hear from a kindred spirit!