I think being turned into a mouse would certainly make your life harder, the reason for that is because of how many predators a mouse has, those being Hawks, Owls, Falcons, Snakes, ect. making the search for food difficult.
Not only that but mice have a very short life span so it's not worth being a mouse.
Being a House Mouse would be a bit more difficult considering they're herbivores and eat fruit and grains, which will most likely not be provided in the environment they're in.
In conclusion, being turned into a mouse would not be fun.