I feel your pain because I'm living it. I feel so low sometimes that I cannot justify even moving. I say to my self: "What's the point in moving your arm, your worthless arm, your worthless life, if you move your arm, you'll still be worthless and your life will still b a mess and your past will still be terrible." So, some days I don't even roll out of the bed. I only get up to use the bathroom after I absolutely cannot hold it anymore (lol, a bit of a laugh). And yes, it's been going on too long for me. I'm your age and I've been dealing with this since elementary school. Medications, psychotherapies, meditation, self help literature, etc. and I feel fine for a while, but I sink soon again.
The thing is that you are not asking complete strangers for advice here. You are speaking to people who live through this pain everyday. I can understand you as if I've known you forever. My pain runs so deep, but I am still here. I frighten myself with my thoughts, but I sometimes feel peace from when I consider miracles. I study medicine and human biology now (ironically) and I come across things that absolutely amazes me sometimes. And then I think: "if that is possible, then there must be a way for me to be happy. I just have to find it." The problem is then finding the strength, will, and motivation to do so. My motivation is my daughter and though sometimes, its still not enough, it is strong enough to make me think logically.
Depression doesn't play fairly. It messes with my ability to think logically at times and it takes away a fundamental factor- HOPE. But, please find a way to refire your faith in HOPE. I will take my own advice, too. And we are all here because we are looking for hope for the better.
-----PLEASE LIVE ON------