I know a psychiatrist with a lot of experience in depression matters.
There are studies about moving a lot and the results are very hopefull.
The problem is that depressing persons don't want to move, they are tired.
Once you can let them move, they make endorfines and are feeling more well.
So, move your body, use your muscles, take a long walk and keep going for a few month's.
Of course anti depressants have side effects, they are mostly serotinine re entry blockers, it will help against depression but there is no medicine what works and have no side effects, it's choosing between two bad things and you have to take the less worst, so, you can try to move, it's cheap, no side effects and very natural and healthy.
Once you do the physically excercise, your head will be more empty of sorrows and you will become less fatigued.
How natural can one have?