Surely enough if you didnt spend btc for those gear, you would have been much happier.

How many btc did you spend for those?

At this rate, you will be lucky to get those btc back by mining.

Edit: 5.1 TH/s = 0.68btc /day at current difficulty.  ouch.....   Assume you spent 6 btc/ miner (which is damn cheap), you will need 110 days to recoup..... with difficulty stay constant....