Do you save hand histories? I'd suggest you do, and start reviewing them.
the site I'm playing on doesnt allow me to save histories, which is really annoying. and as i'm only 17.. i cant actually go on to another site yet. (all of my money is on the site and i can't cash out until i'm 18) I do intend to get onto stars and party once i'm 18 and can move some of the money around with a neteller account.

It's possible that the poor results you're seeing are just cold cards.
I am fairly sure that I'm not making errors, but when i do play on the higher level tables I wonder that because i havent played there enough I dont know how the game differs from that at the low limit games. I tend to find that I over bet my big hands and get no action where as the same bet could expect multiple callers at a .05/.1 game... and because I'm not getting paid off on the huge hands i just steadily go down and then i'll have top pair top kicker or a set, and get some chips in only to fold/lose to a chaser with a flush or straight... and ultimately dont make a profit at the higher table. Perhaps I'm just not spending enough time at the tables to get anywhere??

cheers for your advice guys