oil light flashing on

What is your question?

my oil light started flashing on and off making me think I needed to change the oil. However, I just changed the oil last month so I took it back to NTB and had them check the oil level. They said my oil level was fine, maybe a little over but wasn.t dirty. So I asked them to change it again using high milage oil and drove for about 35 miles and the light flashed on then off for a brief moment. As I drove it this morning the light was off until I had driven about 35 miles and the light came on flashing but stayed on until I got home. What should I do?