So I've royally screwed up my schooling. Any suggestions?

I'm 15 (16 in under a month) and I only have around 10 credits completed. I don't see myself graduating anytime soon, and my motivation is decreasing with every passing day.

The reason I'm so behind is because of anxiety and depression, but that's mostly under control, now. I just want to be done with high school, but I'm really not sure how to go about it when I'm this far behind. I should be in grade 11 and I'm still in grade 9 classes. Any suggestions as to how I unscrew this situation?