If I could set things up the way I want I'd tell my family the story, get a mouse cage and like a few years worth of food and water and such, teach them how to change it around and things, and then show them exactly what would happen. I would write as a mouse stuff out, with my little mousy hands, and whatnot, and tell them it's me and what's happening; tell them it's a weird scientific experiment or whatever.
That way I can live in their place and they'll take care of me and such, hopefully.
But if theres' no prep time?
Well a sparrow can find food and get around a little easier; being as awesome as I am, with a human brain, I can likely avoid predators. Since the majority of issues involving mortality rates with sparrows occur at a young age, being an adult sparrow flying around means I'll have it pretty easy. Since they can live in areas like barns and houses really easily, I'll just go to a mostly deserted area. Without the need to chirp a lot I likely won't attract a lot of attention.