My latest session of NL50 SSS on PokerStars:
hands: 1995
$: -44.15
$EV: 54.94 (This is a stat calculated by Hold'em Manager that adjusts for equity and not performance after the street that you go all-in. Other winnings are not adjusted for (and are the same as your actual $).
I am inclined to think that this is a downswing rather than poor play, but losing >4BigBlinds/100 hands is tough.