RPM fluctuate and oil light comes on while driving

Hi, last night I was driving holden vectra 2001 model, when I turned left on light, the car started to shake, the rmp started to fluctuate and oil light comes ON, I somehow parked the car on side street and restarted the engine and everything was fine. I am pretty sure there is something wrong as temperature sensor for last 2 days is heating up really quickly with just 5 min of driving it climbs till 90C. Any help will be really appreciated. Thanks