You can get prions at any age, so you're not too young. It's just that they can take time to accumulate to the point where they're impairing function in a noticeable way, so the problem is usually only discovered in older patients.

That being said, I echo others who say you're very unlikely to have prions. I have a lot of insomnia too, and generally speaking when I have a bad bout I get all manic and start to have wild fears and get worried about unlikely things. I've tried everything for insomnia and nothing ever really helps, so I can't offer any advice that I can vouch for.

Have you tried melatonin?