With our three children, there was definitely a transition time between when they were getting mobile enough to get out of the swaddle and when they were actually comfortable with being "loose" after they got out. I kept trying to swaddle until they were comfortable without it. The best coping method we found was to search the baby dept of every store we could find for bigger blankets (even finding some 30 x 40 inch ones instead of 30 x 30 made a big difference).
The kids also seemed to feel more secure and stay swaddled a bit longer when I put their heads right in the corner of the crib against the bumper pad. Of course, with all the ways they scare new moms, I had to check them several times and sometimes turn their heads a little to feel comfortable that they weren't going to smother agst the bumper pad, but eventually I calmed down and that worked for us.
Finally, you might be able to ask around (or look online) to find other ways of swaddling. The nurses at the third child's birth used a different method than the previous hospital and it was helpful to have different options to try sometimes.
Best of luck! V. (mom to 4 yr-old twins Jacob and Katie, and 21-month old Aaron)