1999 Nissan Frontier Oil Light

Hi Everyone! HELP!

1999 Nissan Frontier was running great until last week. Even with the high miles 186k!

My oil light comes on while on the highway, and I immediately stop to check oil level. I add 1/2 quart, and proceeded up the road. It ran good, but now the oil light still comes on intermittingly. And now with the check battery light. It now takes several cranks to turn over and the ever present oil light blinks in and out. I do not drive it at all.

Had a major tune-up done six months ago, and oil is changed regularly.

Any suggestions on what to check before taking it to the shop?

Thanks,

RG