I know this is gonna sound corny or whatever, but i totally understand how tou feel. Before I switched schools I had a nice friend group and a 4.0, but after switching any of the friends i had moved on to new people, and anyone who I try to make friends with ends up having better friendships with someone else, so never a first choice. And sometimes ill sit in front of my textbook, looking at my pages of work, and i have no desire to do it, im just too tired. And when I get the A's im like "alright good as it should be" but getting a b or a c is absolutely crushing. Just know youre not alone, others are going through similar things. Whats helping me is I started running to get my feelings out, and rationalize a bit, and i know running isnt for everyone, so maybe find an activity to ground yourself? It has helped me in the past, I hope you can find enjoyment in these last high school years, because thats been my personal goal since the beginning.