32 from MA, looking to loose 30lb need motivation!

Hi there. I'm 35 and have around 30lb to lose too. I've been my ideal weight a couple of times but it's taken quite a lot of work! I don't have a lot of time for the gym with two children although I am always on the move. This time I am trying intermittent fasting (16:8) and a high protein calorie controlled diet of around 1300 calories. What do you do on gym days? Do you eat back your calories? I've found that the only way I lose consistently is if I don't eat extra to make up for exercise.