Yup, slicing significantly reducing driving distance. If the ball is going sideways at the end of its flight then that's all the forward distance gone. Get the slice fixed and the distance will come. Don't worry about your swing speed at the moment but try to develop a consistent and natural tempo.

Slicing is a problem for all new golfers and it takes time and effort to overcome. With some tuition and practice however there's no reason why you should continue to slice. I remember when I stopped slicing the ball, it just happened all of a sudden and has never come back. It's a great feeling when that happens believe me

Best of luck

Paul