Still speak with a professional. Don't self diagnose. I don't know if you have and know for a fact that it's depression, but if you haven't and are just going from symptoms that can be dangerous.

There's a whole slew of mental disorders that might appear as depression at first but are something else, and for some of them, weed can even make them worse than they'd be without it. I speak from personal experience on that. I thought I was depressed, took weed and it turns out it was schizoaffective disorder with major depressive onset. Weed made it much worse than it'd have to be.

I'm not saying that to scare you or anything, cutting off weed and taking proper medication really helped me out personally. But if you're thinking it's some mental disorder, it's always better to get proper diagnosis and medication for it.

I wish you the best regardless. As for the question, when is it too much, the answer was given already. When it starts affecting your life. And yes, weed is not addictive, physically at least, but it definitely is psychologically. If you feel shit when cutting it off, or can only function with it, it's still addiction.