You clearly haven't if you're failing.
This
I highly doubt that unless there's some huge grading error. Nowadays schools have those fancy smancy websites that allow you to view your grades and assignments, over here it's called Skyward. If your county has one of those websites then you could get on it and check the what grades your assignments have and such. After you have an idea of what you need to work on just study and pay attention in class more I guess.
Off topic but I had one of these in high school, except they only gave the login info to parents, and my parents wouldn't give me the info for some reason. So I'd have to ask my teachers for my grade info, but half of them would just say "check the site"
Also the site wasn't connected to the same grades as the actual gradebook, but a separate site that had to be updated separately, so half the time the site was wrong.