Yes holding is the only option for you. In case of bitcoin it is very volatile in nature and these kind of dips will be always there. You should rather take the advantage of bitcoin and its nature of pump and dump.

Most of the people are also in the state as you are who invested big money before and now they have gone all the way down. But they will see it as an oportunity to invest more into bitcoin. As it will profit more after pump of bitcoin.