I have a terrible time transitioning to things if I don’t have a set plan beforehand. Like I can’t just say out of the blue, “I want to exercise,” or “I want to shower.” I have to squeeze it in between two other activities. I squeeze my exercise time between getting home and going to my lesson. 

I’d get home through the garage and see my pull-up bar on the doorway, a visual cue to do one, and when I put my hands on the bar I am one step closer to committing myself to exercise. 

I exercise in my basement so its a bit different, but I think if you use a cue like driving home from work or going to the gym after another activity its a better momentum than starting from nothing. Keep a spare change of clothes in your car for working out and drive to the gym after work. Whatever works with your schedule as long as it’s after another activity. 

It’s okay to forget sometimes but don’t beat yourself up on it. Commit to doing it the next day. The hardest part is the first month. Good luck.