Bitcoin is really a nice investment and despite it's volatility, there are a whole lot of investment and business opportunities in Bitcoin.
It seems from your lost you already have lots of knowledge in Bitcoin already especially when to buy and when not to buy, but the general truth is that we should always buy Bitcoin at every little opportunity that we grab.
Bitcoin has come to stay and it is the investment of the future but one thing that bothers me is the mentality that has been instilled in people as if selling Bitcoin when they make some profit is wrong and this is bad because the general concept of saving or investment is to back something to fall back when the need for money arises without bothering anyone.
I always buy Bitcoin at every instance I get, and I'm holding as much as I can.