Not an athlete no, but I do sport most days.

When my depression was at it's worst I had to force myself to exercise, depression robs us of joy and motivation - you don't write what your dx is, but depression can do this.

What helped me was loosening off my expectations, I wasn't going to be as fast/fit as before, so instead of beating myself up I had to accept that, just getting out there is an achievement - make sure you acknowledge that achievement. Exercising with friends helped too, as did taking up some new activities, adding some variance. If you haven't tried those approaches already it might be worth a go.

Exercise really has helped me cope with a rough patch, but the motivation has been a struggle.

Good luck!