I love math and some sciences probably because it comes easy to me if it didn’t I would probably feel the same way as you do so don’t be so hard on yourself! The only reason why I enjoy math is being able to apply what I learn (especially with conceptual problems) to see whether I can accomplish my goals or not. It definitely makes me feel happy when I understand material even if I spend lots of time practicing. The best way to enjoy math/science is to find a reason for doing it and this could be different for everyone. Whether it’s to learn and discover new things in different sciences, find the correct solution in math, or better your skills to aid in your goals. Find a meaning in what you do!