2002 beetle stalling

I just bought a 2002 beetle turbo GLX it worked fine on the freeway but when i got off the freeway it started to act like it wanted to stall and when i tried to put it in reverse it wouldnt go if i pushed on the gas it would make a reving noise and then jurk into reverse but now it just wont go into reverse at all. Also when driving under 20mpg it made a sound like something was dragging today it still wont go reverse and when i drive it keeps loosing power almost like its going to stall but it doesnt turn off it just wont speed up my speed just drops and jerks alot. Does anybody have any idea what it could be?