Was reading down post, ready to suggest getting underneath and seeing if there is fresh oil on there, seals most likely but finding which one is the problem.
Either get it in a garage ASAP or carry a gallon of oil in the van with you until you can get it off the road, last thing you want is engine blowing.
I have blown an engine due to neglecting this type of problem, also blown 2 turbos.............. I suppose it's called living and learning, and thinking ........... I will sort that out tomora, tomora, tomora.......
Get it sorted in the morning or ASAP. Cost in long run will be bigger.