Never ever give room for second thoughts against your bitcoins. Holding must be the best option for those who have missed out $19.5k levels. At least you must have taken a big decisions to sell around $15k and right now it is too late for taking any decision other than continuing holding. It may sound funny but it is already year long of waiting. This is the time for buying more when it is so why not you just keep holding those already-bought/earned bitcoins.