A bike question
So I was out riding yesterday when I heard the definite sounds of a leak from my rear tire. Since I was in a place where I really couldn't stop I rode on a little ways. By the time I stopped, so had the leak (?!?). Today at lunch I went out to my car to (briefly) look at the tire. It hadn't lost anymore air, and when I tried to put air in I couldn't get the pump to register over 40 psi but I can tell there is clearly more air than that in the tire.
My question is...uh....what the hell?