Can't decide if I should put another 2000 USD in bitcoin now, or wait and see if it goes even lower 
Bitcoin could just as easily drop another $25, $50 or even $100. I would play careful. Only risk what you truly can afford to lose.
The estimate trading widget on BitcoinWisdom shows a single flash sale of 20,000 BTC would take the price sub $200.
20,000 BTC sell offs are not unheard of.
It's possible but it could easily go back to more than 300$ too.