Oil Light Flashing

I have a 1989 Jetta GLI. I had it parked for 2 and a half months and I started it up recently. It started and ran fine, but all of a sudden while I was driving it, the oil light started flashing and it made the warning sound. I wasn't sure what to do so I just parked it. I figured it was because the oil was relatively low and old, so I changed it and the filter. After I started it up, it ran fine, but as soon as the motor spun past about 2500 rpms, the light came back on. I am not sure what to do.

I'd get the oil pressure checked with a mechanical gauge first. Often the dynamic oil system on the cars can fail & give a false light. I'd still tow it to the shop just incase it's accurate.

thanks, it turned out to be the oil pressure sending unit.