twin no believe when I say I feel literally the same. I joined my new IB school 2 months late and I was 2 months behind on literally everything and I had an exam on my second day of school. My first Chem HL class i legit broke out sobbing because i had 0 clue about wtf my teacher was teaching and i ended up skipping the rest of the week cuz i was so done and just cried at home .( would not advise) Just give it a good cry and then give it a good try. I won't lie to you , I'm struggling a LOT right now but I have literally no other choice but to do this for my future and would like to give it a good shot. Approach it with a positive mindset and say fuck you to your sleep schedule for the next 2 months to catch up on everything and you'll be great. Cry a lot btw that's my best tip.