1996 Golf Oil Light

I have a 96 golf and the oil light on the dashboard intermittently turns on and off...I just recently had the oil changed about 3 weeks ago and I drive about 100 miles per week, so I don't think it's the oil? Any suggestions on what it could be?

Failing oil pumps are not uncomon, have someone check the oil pressure with a mechanical gauge. Minimum pressure (when hot) is 29 psi at idle & 43 psi at 2000 RPM.