There's no medical explanation for my depression

It's been that way for most of my adult life, but took a turn for the worse after COVID and getting worse & worse with each passing year.

I'm 30. I don't drink, I don't smoke. I don't lift weights. My weight is 165 lbs & height is 5'8". I don't eat fast food THAT often. It's true that I almost never have the energy to cook, but if I do eat out, it tends to be in the healthier range at local businesses, not McDonald's etc.

I started exercising (push-ups & squats everyday) but then slipped back into a sedentary lifestyle because of a breakup (it was a situationship that shouldn't have affected me the way it did).

My blood tests turn out normal everytime, with only vitamin D pointed out as a chronic deficiency because I live in a cold country.