Moving up and getting beat back down

I have been playing .50/1 NL online ring games for a while, and have been pretty successful. I pretty much always mutlitable 4 games at a time. And have a longterm average win rate of $10/table hour or $40 per actual hour (4 x $10). I want to move up to 1/2 and higher, but it seems like whenever I do it, I get beat up and come crawling back to the .50/1. This annoys me to no end, because it make no sense. The 1/2 players can't really be that much better than .50/1? It must be me, but why? My bankroll can take it! My first try at 1/2 was about a year ago on Pokerstars. I had great success at first, swelling my bankroll up, but it only lasted for a week or two. After that things went south, and I lost all that I had won at that level and then some. I did not have pokertracker back then, but I always kept a spreadsheet detailing my play. I went running back to .50/1 and that was it for 1/2 at Pokerstars.
I then went to FullTilt chasing the 100% sign-up bonus ($600). Might as well get paid to play right? I went on an incredible run on FullTilt at first. It seems like this always happens when you first start playing a new site. Don't think the software is rigged, but it is kind of strange. Probably could be the regulars not adjusted to your game yet, but just a theory. Anyway, within about a week I almost had to move up to 1/2 to find some real competition and I did. I started crushing that game as well making something like $100/hr for the first 10+ hours of play, but as before I crashed, burned, and gave it all back and then some. Back to .50/1 for me. Back to $40/hr but I will take it. I took off several months from the 1/2 tables, but I have been trying it from time to time. Usually 1 or 2 of my 4 tables open with the rest .50/1, and only if a table looks soft. No big run up this time to start, but a slow drift down. Was down about $170 after a while, then rallied to down just $10, and about to post a win to put me in the black, but could not book it. I am down $260 currently in my latest attempt with about 1700 hands played. Hopefully writing this stuff down and analyzing my play will get me over the hump. We will see!