I will be studying for AP European History, Chemistry Honors, and Algebra II Honors.
I’m studying for Euro and Chem too… Sigh… I have no idea where to start either. But, good luck to us both! 
good luck to you too! my chem teacher does not teach at all, so i have to self-learn half of the material. i have to get a c+ or above to maintain my a in chem but i’m still so worried. self-learning chemistry is kind of hard because i only partially understand all the concepts. my final is tomorrow; hopefully i’ll do well though.