Clutch replacement/Rear main seal

Even if that's the case you need to make sure the clutch adjustment has some freeplay, or it will act like you have the clutch partially pressed and slip.
If the clutch isn't fried and needs replacing yet, it will very soon without that freeplay.

Remember you want about an inch of freeplay on the pedal before it starts resisting.

Thanks, I will definitely be adjusting the clutch.