Never sell at a lower price than when you buy. We are here to make money, not to lose them. Even if bitcoin price drops by hundred dollars, it always bounce back. All you need to do is wait for the price to bounce bank. It only takes a few months before the price bounce back when it falls. A few months wait will not hurt. Just be busy with other things so that you will not be tempted to panic sell.
There will always be plenty of people that sell their coins in panic. No matter what their intentions and plans were at the beginning when it comes to holding Bitcoin as a long term investment, they forget about it as soon as they see the price drop heavily. They are called weak hands. Same is, and has been happening with stocks. It will never change.
They actually can be avoided. An important reason as to why people are heavily in panic when the price goes down, is the fact that they use money that they can't miss in their personal life to invest in Bitcoin. There are enough people that just invest money that they can afford to invest. These people mostly never panic when the price goes down and keep holding till the price recovers again. It's not that difficult.