I'm an otherwise healthy, fit cis male but goddamn I feel like any "oommph" I had before starting a workout gets vacuumed out. It might be motivation. It shouldn't be hunger. How do you deal with it? Roughly a quarter of the time I can "aggro" my way out of it and have a normal ~30m workout, but other times nah. Shit sucks.
Are you following a program? You should be following a method that has been designed by a professional that will help you meet your goals. This could be from a trainer if you want it to be (I don't think it's likely to be important), but it could also be from a book or online resource.
Doing your own thing is just "exercise" while following a program is "training" that will leave you feeling accomplished as your performance improves week to week.