I'm going to echo what everyone else has said about playing in the .5/1 ring game. The more common term for that level is NL$100, because the max buy-in (what most styles of play would use) is $100. For ring, you want a bare minimum of 10 buy-ins for the level you're playing, with 20-30 buy-ins being far preferred.

I'm guessing that you didn't buy in with a full stack at the NL$100 ring table. Even buying in with the min ($20), you're still risking a sizeable portion of your bankroll. Further, playing short stack is a much different thing than playing with a full stack. You lack the intimidation power of a full stack, so you absolutely can't play scared - the rest of the table will walk all over you.