Head gasket or fule pump

A compression test will tell you if it was a head gasket. You can borrow or rent a compression tester from most any parts store. It screws into the spark plug hole, so if you can change a spark plug you can do a compression test. There's really no other way to tell if or how bad a head gasket is. None of your symptoms sound like a bad fuel pump, so I wouldn't waste your time pursuing that. (Your symptoms don't sound like a blown head gasket either.) Even a totally blown head gasket would not leak fuel into the crankcase or cause a large amount of smoke to emit from there. On the other hand, a bad valve seal or piston ring would. A leaking fuel injector can play havoc on a cylinder, some of that leaking fuel gets through the rings and into the crankcase (on top of causing misfires or knocking). You look like you have some investigating to do.