2006 Kia Cerato Clutch

Towards the end of some gear changes, clutch feels "rough " and there is a noise/vibration from the rear passenger side of the back of the car sometimes. Sometimes it stalls easily. Problem seems to be a bit intermittent, some gear changes much better than others. Gear changes used to be a lot smoother! Had a fule pump replaced last week, it has not been serviced for 20,000km was low on oil last week, and I tend to ride the clutch with the accelerator a lot, with very aggressive driving for 8-10 hours a day. Since this problem has surfaced in the last few days I have been trying very hard not to rie the accelerator while the clutch is being released, which is hard because the its a fast and sudden release point on the clutch, but that seems to have helped. Am concerned the clutch or gearbox needs work or replacement, but trying to make it last a few more weeks. Should I get it looked at straightaway by mechanic and avoid another tow, or is it more likely to be something annoying but minor I can keep going with for another week or three?