Any time that bitcoin market price is declining the next this you should do is to buy at that cheaper price and hold till when the its price appreciate again and in doing that you will make profit and at the same time you will help the market bounce back to its fullest height.
Good point on the take profit at 12.5K. There is a lot of resistance at 13K, so it is a good idea to take profit before it hits it, but with the way the trend is going, if it reaches past 12K again in the near future, I think it will explode towards 15K.