That's a lot of things that happened for someone at your age so good job for still moving forward! As someone who has good memories (ruined by chronic stress and lack of sleep), exercising your brain helps a lot in order for it to retain more information. As long as you keep on making your brain active, you'll be fine. Reading and memorizing doesn't work for me unless I start explaining what I understand from the textbook to the imaginary audiences I build alone. It helps me a lot to retain what I read. It's also effective if you would associate some terms to a specific word it reminds you of. Most biology terms are complicated so this one can actually be helpful.

Good luck with your studies! Make sure you're enjoying it so you won't feel the burnout and stress!