If you have taken profit on it already, don't blame yourself and don't regret. This is happening not only to you OP but to every traders that wants to sell what they have.
You should assign some of your coins that's good for long term holding and some of your coins that are good for day trading or short term holding.
I think we all have a version of this story.
Yes we do have the same story and this is the reality, we don't know when a coin will pump or when it will be dumped.