Astra oil warning light?

hey guys

i have a 1997 (P) MK3 Astra1.4 8v single point injection it has just over 112,000 on the clock and generally runs pretty well, its just had a full service at 110,000 (by me) with decent parts from halfords

Last night when i slowed at some lights the oil pressure light came on so i pulled over to inspect the oil level, i noticed that once i applied even very light throttle the light would extinguish then return once the engine was at idle so i stopped the engine to check the oil level which was fine so i drove the car home /9a very short distance) and went to bed as it was late and i was tired

So i come to drive the car today and on start up with engine cold the light stays off only to come on at idle when warm, after looking at some sites they suggested it could be the pump which would fit given the mileage and the fact the light does flicker sometimes

I have since put an oil treatment in from STP designed to offer better lubrication under load etc... this didnt do anything until i came back from manchester to burnley and ok maybe i shouldnt drive a car with low oil warning that distance but when the car was driving there was no low pressure light and the car drives normally, tonight i came to a stop outside my house and no light i let it idle for about 5 -10 minutes still no warning light

so is it a fault thats cleared itself or do you thik it could come back, do you think its something else other than the pump?

any answers would help thanks