I'm not sure if this has been asked before but, how are you valuating your porfolio? Are you using the historical cost of the initial btc you invested with or are you valuating with the btc price changes?
EOD (End Of Day) quotes in BTC, then translated into USD. That way you have both BTC and USD valuations. For the reasons cited many times before in this thread, everything here is current, real time, EOD USD.
The same thing that Coinmarketcap does, just that they do it averaging over all listed exchanges, and I only use Bittrex data.
http://coinmarketcap.com/