honey and sting

So, for reasons, I need to lose 50 pounds. I've started with a trainer, who has experience dealing with people with chronic illness (in my case, crohn's disease and its associated arthritis). We've had 3 sessions and have been going what we both feel is a nice, gentle pace. However, after the last session (to which I added a two mile walk that felt quite lovely when I was doing it, not pushing at all), I had an all night inflammatory response resulting in pains all over my body and very poor sleep.

Has anyone had experience with this and how to manage a new exercise program as a middle aged person with a body that tends to get all inflamey? I've maintained good range of motion with daily "bathtub stretches" and an occasional gyrokineses class. The issue is with adding more strength-challenging things, like machines and gentle weights.

eta: compounding the joint issues is that I've started on an aromatase inhibitor (to prevent cancer recurrence), which suppresses ALL THE ESTROGEN. So, on top of menopause, and menopause, gold card, for stopping HRT, I am in SUPER-ULTRAMENOPAUSE.