It's unfortunate that you don't understand what Cain is talking about. His points are right on (although doubling down in a loss is a terrible idea).
The basics of investing require that you have a plan before you buy a stock. What to buy. What's a good entry point. What are the reasons you're buying & what would need to happen for you to get out.
If you did all this before you bought...... you wouldn't be panicking. You'd either hold on or sell... fear would not be in the decision process.
I own S (I actually trade it a lot)... for the past year. It's at the 61.8% entrancement point (5/7/10). Many traders would run at this point. I'm holding on to my shares. If it breaks the 200 MA ( $4.04) I'll be out.