a few years ago I was having quite a similar issues. my depression and anxiety got the best of me. i even used a write my paper for me website but one day i just decided to take everything in my own hands and try to do the job on my own, though i did suck at it, it tried my best. the first thing i did was joining this course on how to learn math. not sure whether you can still take this course but you can inquire whether you can enroll. also i love MIT open library -- here are some high school math related courses
god luck