Hi Tonic,
It's a messy job to do but the oil may be struggling to get through your engine. I've done this myself at home and I'm a long way short of being a car mechanic!
Drop the oil out of your engine, remove your sump-lots of screws and a couple are quite tricky to get at, then look for the pipe that pulls the oil up from your sump, remove and clean this. When I did mine it was clogged with all sorts. I took mine to work with me and cleaned it in a tank of mysterious but powerful cleaning fluid. I was also getting my oil warning up and this curred it, plus it's a cheap thing to try.
Good luck