how do you tell if your tranny is going or the clutch

If it moves at all, the transmission is working. This is a manual transmission, right? If the clutch plate is worn, it is too thin to be squeezed and held between the pressure plate and flywheel, so it slips. The little friction it can still produce is what makes the car creep ahead a little. Trying to drive it like that will cause the parts to heat up and warp and / or develop "hot spots" on the metal friction surfaces. Those can not be machined out when the flywheel is resurfaced so it will need to be replaced. If it hasn't been overheated yet, it can likely be saved and reused.