If you sold your BTC in July, now you can buy them back with around 20% profit.
Nobody can say why you sold your bitcoin because it depends upon your needs. Nobody knows your personal problems and situations. You just told that you sold all your bitcoin but you didnt mention the reason for that. If you would mention the reason for selling your coins, then we can give our comments in the right way. Now what we can say about this?
Selling and buying bitcoins for profit or for need is one's personal matter. Many people can't hold longer because of some financial needs and many will sell in panic. Then there are traders who keep on buying and selling and booking their profit from this volatile currency. Everyone has the freedom here and everyone is responsible for their profit /loss and their needs.
if you're not greedy bitcoin always gives you opportunity to make money. You can start it again and bitcoin will pay you back with profit.