I also have the same thoughts as you because if viewed from the graph that happened with bitcoin in 2017 experienced that much price increase, surely the prices in 2018 will fall like this and then the prices in 2019 should be able to experience price increases because as you give an example like the one in the market cycle.
Yes its a cycle and because of that we cant see the market to continue pumping without experiencing the dump price, its normal to be like this and we should be used on this kind of trend. After the fall expect the moon to rise again as we are still moving forward for a higher price in the market. But of course stop selling your coin at a loss, that is too risky.