This thread is making me worry even less. I had just bought a bunch of shares because of selling puts that unexpectedly expired way in the money. Only slightly earlier, ANET had gone to $300, and I slept well and decided not to buy back the puts. Then I woke up and discovered that ANET was now over 15% of my portfolio.
But I know that if I sell calls on it now, the calls will go into the money just before they expire, and I’ll be left with a huge opportunity cost.
I think I’m safe before too long - give it another quarter or two, and when Mr. Market will get manic again.
One thing that might scare me off is if Jim Cramer says it’s a good buy opportunity now. 
But sometimes he’s right, just like a stopped clock.