I started my car, it made an odd tapping sound, so I sat for a minute in park, and as the engine warmed up, the noise stopped. Drove less then a half a mile, and my oil gauge suddenly dropped to ZERO. My 'check gauge' light came on, and I didn't even have time to pull over before I noticed smoke behind my car. Pulled off at the next street, and noticed it was actually coming from my engine! When I got out and looked, the engine was clean, but under the car was a huge puddle of oil. I had checked my oil earlier in the day, like I do most Sundays, and it was perfect. I do regular oil changes. Car has 120,000 miles on it. What could have happened?! Does anyone know what it could be?! Thank you so much. Single mom here, I just want to know what I am looking at, repair wise, so that I don't get completely ripped off... 