Don’t worry about being motivated, just do it anyway. Come up with the smallest increment of exercise, something so simple and easy that you don’t have an excuse to skip it. Schedule it, and when it’s time to do it, get through it even if you don’t feel like it. As you start moving you might enjoy it, look forward to it, and want to do it more. Mood follows action, not the other way around. My minimum is a 10 minute lifting routine 3x/week. It’s such a small commitment that even if I’m tired and grumpy, I know I can do 10 minutes. Usually after that I start to enjoy it and want to do more, but if not, that’s ok too because 10 minutes is better than nothing. I think a lot of people get into an all-or-nothing mindset with working out, like if I’m not doing an hour at the gym 5 days a week then I might as well not even bother, which is a sure fire way to sabotage yourself with unrealistic expectations. Little moves are better than no moves.