Early stages of dementia or alzheimer's? what do i do?

I am 14 years old and i think i may be developing something.. huge chucks of my memory have just disappeared.. for example its 21:10 right now and i cant remember much before 12am.. like getting up, doing my paper round, having breakfast.. i've just gone blank! i cant remember anything of yesterday except for doing my homework up the kitchen table.. and im not even certain on that. i have always been quite clumsy, like misplacing things and going downstairs then forgetting what i was going to get.. but its getting pretty bad now.. it all started a couple of months ago, but now my memory is getting worse and worse.. what should i do?