What needles were you knitting with? Some knit differently on say, bamboo compared to metal.
Were you afraid they would fall out? Does this happen when you're not knititng in the round?
Here is a good article: http://www.knitty.com/issuespring05/FEATloosenup.html
If you're really having trouble, is there a LYS or someone you can see for help? Blisters are pretty extreme, and I'm wondering if it's something that could be easily fixed.