I can't figure this out...

I've been struggling with depression since I was 16 years old. I am now 24 years old. I can't seem to figure this out. I've seen many therapists through out the years and I can't figure out why I feel the way I feel. I am so tired of feeling this way. I am so tired of dragging through life. It's like one big gray cloud is following me and I don't know how to get rid of it. I'm not even sure what I hope to get from making a post on here. I just don't know what else to do.