Did the pattern tell you to slip the first and last stitches? Is it possible for you to take a picture of the bag?
Regardless of whether or not you can fix the mistake, if it's not turning out how you want you might be better off anyway. I hate frogging... but if something doesn't look right, feel right, or turn out to be what you thought, why spend all that time knitting something you won't wear, or use? Otherwise it will just sit there, and you'll look at it and thinkng "damn, if only i hadn't screwed up that one part I'd wear that sweater/bag/sock/mitten"
someone else jump in here! i need help helping! Or maybe i'm not helping... I need help NOT messing up cpolitte more!!!