losing oil on 2001 Cadillac DeVille DTS

after driving approx. 100 miles on a new oil change the check oil light came on. was in the boonies & drove about 3 miles. checked oil and was only about a quarter inch on the dip stick. what could be my problem

1 answer 1 comment
check for leaks at the filter and drain plug.did they put enough oil in?
oil in water but not water in oil