I can't point you in the direction of a specific agency or program because I don't know if you're in college or younger, and that has bearing on what advice I'd give you about that. But, I can make some suggestions regarding instructional strategies and interventions.
You may want to check with a properly qualified optometrist to see if you would benefit from vision therapy. Potentially depending on your age, this may or may not be something that would work for you.
When working out your math problems, use graph paper. You can get graph paper with large grids, small grids, etc. I've provided a link below where you can create your own graph paper and make the squares as big or little as you want for free. It creates a PDF that you can download and print as much as you want.
Using graph paper lets you line up the numbers so you don't accidentally use the wrong digits as you're working out your problems. Being able to adjust the size of the squares helps you work out the spacing to accommodate your visual processing issues. Keeping things lined up and tidy also means that if you ADHD in the middle of a math problem, when you come back to it, it's not going to be a nightmare trying to figure out where you left off.
I was fooling around with the graph paper tool at the link below and thought that using 2 lines per inch was a pretty decent layout, but you need to figure out what works for you. Four lines per inch looked too busy in my opinion and you want things clean and uncluttered so your visual processing centers don't command so much of your concentration, which is limited because of your ADHD.
If you can keep your own notes of solved problems in a readable format, it's going to make it easier for you to retain your understanding of the actual process you're trying to learn. When you're trying to make sense of what you've written, your brain is involved with that rather than understanding the concepts being instructed.
I also suggest that you take the sample problems in your math book(s) and those given to you by your teacher, re-write them on the graph paper, and solve them with the book/notes to help you figure out if you got them right. Using the sample problems in the book where they show step-by-step how they solved the problem as practice will help you learn the steps to solving the problems while having a way to make sure you did it right.
Hope this helps!!!!