About 2 weeks ago, I noticed that I would be leaving small puddles of coolant when I parked my car. 2 days ago though, I noticed that a surprising amount of exhaust was coming out the tailpipes at a standstill. Once I got moving though, the exhaust would go back to what seemed like a normal amount. These clouds are getting bigger and bigger now though. I shoot out massive white clouds when I am going 5mph or less. I also noticed that my coolant level is dropping rapidly. What could be going on here and what can I do to correct it?