My Crown had her oil changed 8 days ago. I drove it home and once the next day to church. trip was about 10 miles round trip. I went out to go this morning, this is a week later, and all the oil in under the car, nothing in the car. light does not come on but is making horrible sound. I wonder if they did not put the plug all the way in right?
Don't start the car! From what you said, it sounds like they might not have put the plug in all the way. This is pretty easy to fix, but you might contact them, as it sounds like it's their fault, and they might be able to help you with it.
If there's oil under the car, that means there's at least less in the engine. Slightly too little oil could be fine, but if you lose too much your engine won't be lubricated, and it'll wear out the inside really fast. This is really bad for your engine. If, like you said, the engine is making bad noises, you should not start it again until you've put the correct amount of oil in.
To do it at home, you would just get a wrench and screw in the oil plug tighter. It could also be leaking from around the filter, so you can try to tighten that (it doesn't have to be too tight). Afterwards, pour engine oil into your engine until the check stick reads normal levels.
If that is not it, try replacing the oil filter housing gasket. This is a common failure item that will cause oil to drip from the filter while the engine is running. The gasket is made of a plastic material with rubber o-rings molded in. They can crack or blow out with age. The stress on the housing from just changing the oil filter can cause this failure on an old gasket. The 15 year old plastic and rubber has lived a good life. The replacement part is about $15 - plus a quart of oil, a gallon of antifreeze, & few hours of your labor. A 10mm gearwrench for the last bolt on the power steering pump will save you an hour or two lol