fluctuations like this will be common unless people start using their coins to actually do things - like buy stuff. If the coins have no use then people will hoard them hoping for another $30/btc day. The more you hoard the less the value of your coins are. Speculate a bit if you want, but if we don't spend and encourage a Bitcoin economy, Bitcoin might die.
I hope to solve this issue with my up and coming retailing website that will be an Amazon clone(i guess you could say), of course my pride will tell you its more then then a clone but you will have to see for your self once its released in September.
For the Bitcoin community to survive we need more outlets of purchasing power.