I've been currently making the retransition to NL25 myself,and at one point was anywhere up 2 buyins to down 5 buyins to up 3 buyins to back down 2 buyins through 8000 hands.I think most of your examples are ok;there's not much you can do from flopping a straight and losing to a higher flopped straight;flush losing to higher flush/set over set/and two pair losing to set are hands you basically will go broke on hand.Post some hand examples from this downswing and we can see what's up;if you feel the need to you can drop back to NL10 for a while to work back the confidence(I might just drop back to NL10 or .15/.30 for a while myself to see what's up.