What were your stats in the 1/2 before you moved up?
I've just popped down from Party NL400 after 5K ~ break even hands.
[I had moved up after a sustained 8-10PTBB/100 (2-4 tabling) at 1/2.]
I ran quite bad during this 5K period, but felt fairly clearly that there were significant leaks/weaknesses in my game.
I think the Party 400NL full ring is not that soft - it's full of tight players who aren't that weak.
As a result, consistent mistakes in small/medium pots don't get hidden by big wins where idiots throw money at you (as happens in the 1/2 game).
[Mistakes not being hidden is a good thing in the long run, of course!]
I suggest:
(i) some honest hand and stats analysis of your game based on your last 5K hands - when you called/bet when beaten, when your bluffs were called, when you didn't value bet a winning hand, consistently losing hands etc
Having identified some leaks...
(ii) move down to the 1/2 (including playing some 6 max to improve hand reading). Play 2 tables some high % of the time so you don't compromise getting *decent* reads on opponents (rather than just "weak/aggressive + loose/tight").
(iii) Rebuild to a 400NL bankroll (or +$3-4K if you already have one) and try again
