2005 Mazda 3 Not shifting

I recently purchased my 2005 Mazda 3s from its first owner. Recently the engine has been revving up a lot when I what shifted into higher gears it acted as if it was still in a lower gear. Right now I am on the side of the road with my car not shifting and smelling like smoke or at least something is smell like burning plastic. My suspicion is that my clutch is going out but I am wondering could also be something wrong with the transmission. In no way would I consider myself a mechanical expert, so it could be something completely different. Can you give me an idea of what it could be before I take it to a mechanic? Thank you