my 07 impala has an oil leak some where seems like it's blowing to the back.

Before you go to the crankshaft seal, check above the oil filter. There is a gasket between the oil filter housing and the block which is notorious for leaking (as is the current issue with mine). The new gasket is about $10 from you local dealership, and the repair is about a 4 on a 10 scale of difficulty to replace (due to having to work around some other parts). It's not a pressing matter, as long as you keep oil in it. It won't cause a catastrophic failure while driving, but the oil on the garage floor and the rear deck is annoying.

Blowing to the back of what? the engine compartment? or under vehicle? Try looking into the cylinders at the spark plugs and see if there is oil sitting on top of them. If so, bad valve cover gaskets. Could be a crankshaft seal as well. Lastly, oil pan gasket needs inspected as well.

Sounds correct. The blowing back could be wind from driving moving the oil everywhere.

look down at the back of the engine where the transmission bolts up to the engine,is there oil puddling there? If so there is an oil pump drive shaft there and the seal there cracks and then leaks. You have to take the upper intake manifold off to get to that shaft and change the o-ring seal

Engine size would be helpful here!... Different problems with each option!!.. A UV sensitive additive can be used to locate source of leak!!!!!!!

It sounds like the oil pressure switch. Located on the oil filter housing, they are easily bumped into while performing an oil change. I did this once myself and your description matches what was happening when the switch started leaking. It was a lot of oil in the same spot seemingly blowing backwards from the oil filter housing area. $15-20 at AutoZone and easy to replace if you have a vacuum switch socket and a little bit of brains. Good luck!