Anyone have any advice for memory help?

I'm a teenager, but I have horrible memory- It's not common in my family so I know its not genetic. It wasn't obvious in my childhood, but it wasn't sudden either- Just gradually started getting worse into my teenage years. Not anything related to health (as far as my doctor knows) but I really need to work on it because it's messing with my school life. Even though I'm online, I try to study a bit above my grade by myself to feel ready. I used to be really good at math, I'm good at most things in school but when it comes to remembering how to do things/what I'm even doing, I get really dizzy and get headaches; Requiring me to take breaks which will likely only hinder my progress since it happens so often. I have ADHD and I assume that's the biggest part in this. I cannot take ADHD medication currently due to bad experience with meds. I've been trying to read things and do recall writing [mostly reading, writing a summary of what I remember and comparing it to what actually happened] and a few more recall things but I do want to try more.

I am yapping, probably spoke too much for a simple question but I mean..