Yes, this is the natural up and down of it. Wow what a run, 1800! People are going nuts, I agree with your bottom estimate as previous to the most recent high it was very stable at ~1250. I feel with current hashing difficulty, it will never again go below ~1100 as no one would mine it at a loss. The Chinese seem to be adopting litecoin fairly well as an alternative, to bitcoins current difficulty, but Bitcoin is here to stay as the entire cryptocurrency ecosystem relies on it as a doorway system to the digital economy. Sell at or near the tops, then buy other coins until it bottoms then sell off all coins and buy more Bitcoin, this is what I do, I do very well with this strategy as when btc goes down it is usually when people are buying more alt currency.