Out of shape

Ok today I started making myself condition for lacrosse. I can't believe the season is almost here so I decided I should start getting back into routine. Good idea. It's not that I am fat I'm not even chubby but jesus I need to start working it. In may I was in perfect condition I could run for two miles without even breaking a sweat now I am like dying after just one. Well I guess it's a good thing I am starting now. Anyone have any endurance ideas?