I too have this problems sometimes. Its really bad in the micro sitngoes because everyone is willing to push with darn near anything. That's why I would really like to get my bankroll big enough to be able to play at a higher level
lower limits are far easier than higher buy ins my friend... get to the 15+ buy ins and your left with 4-5 regulars and a 3-4 fish.. lower your looking at 1-2 regulars and the rest fish... generally fish play loose early(bad) and tight later (really bad)
so when we play super tight early on, conserving our stack, then when the blinds and stack sizes are right, we turn up the aggression and shove all in super loose on their blinds.. they dont adjust to it and we make profitable play after profitable play...
if you play in a higher buy in, every one generally plays the same, they adjust to you, so you need to adjust to them..
example
i play the 15+1 sng on stars, was doing quite well, but after a while my roi drops and i go on a downswing.. variance perhaps? no, say im in the sb and its folded to me, i have around 10bb's i shove any two cards, it used to be a profitable play for me, until the regulars adjusted and start calling looser, with around 35% of hands its perfectly fine to call me there... so i needed to adjust to that, so i folded the last 20% of hands out of my range, all the pure junk, 6 3 8 4 etc.. now its a mistake for him to call with that same 35% and once again, the play becomes profitable... and thats only one facet of how you need to make constant adjustments to your game at higher buy ins..
anyways enough babble.. to summarise, perhaps you should master and beat the lower limits before even thinking of moving up.. you will most likely get owned..