Congratulations on 2.5 months and on getting into the gym as well!
I am only into Day 4 but have exercised consistently over the last 5 years. I found the good feeling I get from exercise is different what I had from drinking. Like you, I know I will feel bad if I don't exercise and I did used to sometimes "force" myself to do it (even when drinking - I would use the drink as a reward - a fine way to undo good work). I have never regretted getting my foot in the door of the gym because of the endorphin high afterward.
My personal view is that regular exercise is a must-do for everyone (alcoholic or not, in recovery or not) for optimal physical and mental health and to 99% of people it will feel like a chore to get started.
Perhaps you could set yourself some goals to achieve, e.g. a 10k run, if you're into cardio. There is a great emotional high in crossing a finish line of a distance race you never ever thought you could run!