Exercise Post Surgery

I am 3 years post surgery and for the past 6 months or so have been playing around with about 8 pounds, up and down the scale.  I must admit for the past year I only walked [approximately 3 miles, 5 days per week] and did not do any other exercise.  I think I burned myself out at the beginning of my surgery becaues I was exercising 7 days a week.  I am now back to the following:  walking 5 days , about 3 miles per day; mixing jogging and walking for about 45 minutes on one day and using my elliptical for 30 minutes a day - 4 days a week [M, T, Th and F].  I am just wondering if I am exercising too much again, which is what some are saying...any suggestions for a good/safe exercise regime.