Basically the "if you don't know you shouldn't own this stock" is the best response.
On why it's going down you probably saw (or should have) saw lots of articles talking about it being over valued. They were true. The sky high price was based on the idea that Tesla would not only be profitbable but keep "beating" estimates for the forseeable future. The same way they did for Q1. That's why it went up 8% a couple days ago on everyone predicting another beat. Now that they actually missed it's coming back down as speculators get out. It's not by how much they missed by as much as the fact that they didn't beat when everyone was predicting they would.
Wall Street doesn't like TSLA's accounting.
Play it on the down side until it stabilizes.
Don't just play it one way.
Love Mr. Musk.
Love the car.
The company is hanging in there pretty good, but it's overpriced.