Does hard work always pay off?

So, the academic year is coming to an end and there are so many things I feel like I have either failed at or just didn't fully accomplish. I've been thinking a lot lately about how "hard work pays off". Let's be honest, hard work is important and hard work doesn't guarantee anything in life. Nothing does. It just feels like there are so many things I've tried to accomplish but I literally canNOT reach them. The more I think about schools, college,  and everything else; the angstier I become.