Total noob here, question about tire pressure/leaks/flat??? I was forced off the road a bit and my back tire sunk into a wide crack between the pavement and curb. I immediately noticed it was sluggish after that and when I got to my destination (about a block away) I felt the tire and it had lost about half of it's pressure. I walked it home later and put more air in it, left it overnight and checked again this morning. It's holding fine and I'm riding it to work today (no time to take it to the shop yesterday, close early on Sundays) 

Is this something that can happen? Lose a lot of pressure without puncturing the tube?  If it's fine all day can I avoid the shop or should I take it in tomorrow morning? 