1994 Honda Civic Oil light comes on when car is iin idle/tr

Car is using some oil, let it get too low a few times. Seals have been replaced. Sees to run fine but after about ten or fiften minutes, oil light will come on when it is idlling even though there is enough oil. Anything to be concerned about?

Also, reverse has gone. Drive works fine. Need to get it looked at. Hoping I just have issue with reverse but wanted an opiinion before I take it to shop. Afraid someione is going to get me ro replace entire transmission. Had an Accord in the 80's where it was just the reverse that needed work. If other gears are still okay, do you think it should just be reverse that needs work.

Thanks or your help.