Dementia in a young person

I've had it for about a year and half or two years, along with severe derealization and other misery. I also have physical health problems which may be causing my organs to fail (including brain function), but it has yet to be determined. I'm only 17, and dementia is typical for seniors, does anyone know if it will get any worse? I've tried a million things for my mental problems and nothing has worked, physically I'm improving however. Anyway, it's not fun to live with at all; very obstructive to everything. Are there things I can try to at LEAST be able to remember things that happened earlier the same day? Or recall memories from a week ago?

How long do you have memory loss?