I'm thinking this could be an issue you could solve only through therapy (whether actual therapy or self therapy - I had success by applying cognitive behaviour

I'm thinking this could be an issue you could solve only through therapy (whether actual therapy or self therapy - I had success by applying cognitive behavioural therapy concepts to myself). Exercise causes you to release endorphins - it's normal for people to feel better or experience positive effects after exercise. Maybe it's the type of exercise. I would start by walking / light yoga and try to add up to it until you hate it. We're animals, we're meant to move and your health will suffer if you don't.