I feel like college is making me dumb

In high school, we practiced all sorts of critical thinking skills and creative problem solving. I feel like most of my classes (I'm an engineering major) are just a game of finding the right equations and using them in the right order. I feel like I'm losing a lot of the skills I once had and it scares me a little. It feels like it's harder to think. I'm not as creative as I used to be and I struggle writing essays which would have been simple when I was in high school. Similarly, I'm losing the drive and work ethic I used to have. I'd survive off three hours of sleep a night plus a few naps and I'd work nonstop. What happened to me?

Maybe it's a covid thing... anyone feel the same way?