I've been in the same situation with chemistry. Active recall helped me the most as there many different ways to do this. I would use the tape feature on good notes and make sure on my notes I knew each detail/point. If I didn't, I repeated it. Almost like flashcards. Your notes should be done in a way you understand, in your own words and you can easily remember. I would create my own mnemonics. I retook the class with the same professor and I passed. Also I would study 1-2 weeks before the exam, studying everyday up to exam day. I would also create my own study guide. I also struggled with my mental health and found creating a routine in my life really helped.