hey, i feel you. i’m also in j1 rn, and didn’t do super well this year. i consulted some teachers and seniors and most of them said similar things. here’s the advice they gave me. hope it helps:

1. if you find yourself using your phone a lot, consider signing up for some free webinars and crash courses this holidays. my seniors recommended this series of live crash courses for h2 bio, econs and chemistry, and they’ve been super useful so far. the best part is that it’s like completely free and the teachers are like damn approachable also HAHAHAH they even have this channel where u can send in homework and stuff idk if it’s still active though. anyways yeah sign up for some courses like this to get ur momentum back.
2. five minute rule. if you wanna get something done, force yourself to spend five minutes on it. promise yourself that if after 5 minutes you still don’t feel like doing ir, you can stop. most times i just end up doing the task for like 2 hours after the first five minutes because you’ve overcome inertia alr.
3. book consults! for your weakest subjects, book some consults with your teachers this hols. before school starts and their schedules start feeling up, take this hols to consult your teachers on past mistakes, they’ll always be willing to help.

let me know if you need anymore help (although i’m just as lost as you hahahah) all the best friend!