That chart is erroneous. It doesn't account for the change in blocktime and thus erroneously shows a hashrate that is twice as high as the actual hashrate.
Damn. So on the uptick, but not as much as that chart would suggest. Is there an accurate one somewhere?
Nothing wrong with your graph, as long as you disregard the MH/s (changed due to the fork).
EDIT current network stats - Difficulty: 2140418213