Hey i had my car checked over when i first bought it about a month ago and was told that my clutch was worn and should consider replacing at some stage.

So its been about a month and ive noticed more and more recently what i think is the clutch slipping. Ussually it only happens when down shifting and generally at low revs but today it happened when i was going up.
Was in 1st at about 5000rpm and changed to 2nd and it revved back up to 5.5 so fast but felt like i got little power...changed to 3rd it corrected...

Does this sound likely to be related to the clutch or are there other possibilities?
My car is a 96 rx with exhaust and a couple rice mods