NEO right now is doing the same as ETH did some months ago. The coin is going up and up and up like a rocket and people think this is going to last forever but I don't think so. Maybe it can continue going up but the coin will drop at some time.

In my opinion you sold your NEO too early but is acceptable. If you buy more NEO, don't sell, just hold them for the long term and you will see how you make more money than trading :)