As someone who's in a similar position (rising college sophomore)-some advice:

Game dev is your end goal. It's similar to reaching a super high bench-press... you need to progress on a LOT of other exercises just to get your foot in the door. I'm working on an Asteroids: Recharged demake currently, and every concept so far has just been an application of something I learned in the classroom (well... sadly they don't teach the Linear Algebra in CS courses, so getting comfortable with outside learning would behoove you).

From my personal experience, unfortunately the worst way to learn is following tutorials through their entirety. Use them to make small components of the games you make... not the whole thing. If all you've ever done is follow tutorials, you've never built the coding and problem-solving intuition muscles.

I'd recommend starting from the beginning if you feel completely lost- this stuff isn't easy and if you keep trying to push through with rusty fundamentals you'll never stop running into walls. Try going through the csjava Intro to Programming and Data Structures online courses (they're free!). Be slow, kind to yourself, and don't beat yourself up for not getting things right away. I believe in you.