I can't stay in class because there's to much light and my assistant has to be with me

As I've said before, you'll need to find ways of doing things that don't involve using vision. There's no way around it.

At this point, your IEP needs to be redone if they aren’t already working with you on ways to get stuff done without using your vision. Half a day being unable to use it means you’re vision is useless. It’s time to own up to reality and learn some blindness skills if you want anything out of life. Dragging your feet only makes it worse.

Maybe learn braille.

OCA is oculocutaneous albinism

I don't know about your vision, however, I have OCA. In my school, (which is in Nova Scotia), I don't have an assistant, I do fine on my own. However, I do have what we call adaptations. These are done by resource teachers to ensure that I can do everything, though slightly modified.

For example, I do everything in electronic format. This way it can be big, and whatever background and foreground I want.

I have an iPad w/ apple pencil, and a laptop. They get me through just about anything.

Finally, as for the light, our school has our lights on dimmers, and my teachers just keep their lights quite low, and if it's a bright day, I can close the blinds.

Hope this helps.

If my remaining vision were causing me pain, discomfort, and a lot of fatigue, I'd just... not use it.

There's a tipping point where it becomes easier to just stop relying on your vision. If you're spending hours a day sitting in a dark room, it sounds like you're past that point.