Lost65lbs from mar-dec last yr from dieting.since dec i i have gained 3 lbs going bk to old diet. does this sound normal w/ no exercise?

Yes: Dietary modifications can alter your weight in either directions. I have always believed weight is a poor indicator of health, however it is quick and easy to measure, so that is what we base our health upon. This 3 pounds could easily be water weight. It's hard to say. A full-body DEXA scan is the most accurate way to evaluate body composition, not simple weight gain or loss.