Failing

I was a top A student last year (I was grade 9) but ever since grade 10 started I've been failing. I recently wrote my Physics test today and I got 33%. I study so hard for these tests, since I struggle with Physics, and my overall average is 27%. I work my ass off and I still fail. What am I doing wrong? My marks are so bad I feel like dropping out. I'm such a failure in life I don't know what to do.