If you sell now you will be regretting when bitcoin get to $50,000 or $200,000 in some years to come as it has happened before and most times we regret selling too early.
Keep holding and the future is for you!
Of course, there's always that big possibility that bitcoin will have it's another day in the sun so to speak. So if you accumulate at 2018-2019, then you should hold on it and wait till the price goes to the moon again.
Some are saying that a lot of similarities in the 2014-2015 graph with 2018-2019 of today. And we all know what happens next in the previous years as bitcoin grows massively and peaked at $20k. The only question is how big is the next bull-run so we better hold and look fo long term.