@Volublekoala966 i can relate to everything you have said. although, my grades haven't significantly dropped (yet) from the sudden change from in-person to online, and then, from online to remote, it's definitely not the best i can do & i'm not incredibly satisfied, but that's just that.
though, i transitioned from online to in-person, i feel like it was not as hard for me, because i only assumed in-person after summer break and during my new year, so it was not during the same semester as we did learned a new material from the very scratch.
i think switching to in-person all of a sudden in between a semester is quite challenging, but i'm sure that you'll do just fine! i don't really have many tips for how to do better in school, but since i learn best with both a visual & hearing (aka basically learning live from a teacher), i like to binge-watch videos every once in a while to study & understand the concepts. if you're learning physics/chemistry or something related to science & geometry/algebra ii then the organic chemistry tutor on yt has always been really good. so check that out if you need it!
remember to not stress yourself out & take everything step by step, slowly but surely. you can do this.
i believe in you (づ ̄ ³ ̄)づ
with love,
xx helene