Crankin - If you don't have one already, I would encourage you to get a hr monitor and really watch for signs of over training. Especially as you are recovering from an illness and have some health issues, it may be very easy for you to do too much (much less than you were used to can now be too much!) and once you get into that trend it can be hard to get out. Many people as they see their numbers drop feel that they should train harder, which exacerbates their over training, makes them slower, so they try to train more - its a downward spiral... when what they really need is some rest and recovery.

Signs of over training: (yeah - unfortunately they can all be symptoms of other things too... I think elevated resting HR is one of the better indicators)

elevated resting HR
Washed-out feeling, tired, drained, lack of energy
Mild leg soreness, general aches and pains
Pain in muscles and joints
Sudden drop in performance
Insomnia
Headaches
Decreased immunity (increased number of colds, and sore throats)
Decrease in training capacity / intensity
Moodiness and irritability
Depression
Loss of enthusiasm for the sport
Decreased appetite
Increased incidence of injuries.
A compulsive need to exercise