Whew, thanks ladies! Glad to know it sounds like everything is okay. Yep sometimes we burp her between breasts, but the last bunch of feeds she is falling asleep after one breast and hasn't made it onto both in awhile. Then I just keep her quiet and still in my arms for a bit and she does okay. Still some spit up but not as much. She will definitely have more if she takes both breasts close together.
Hilary, if this happens, wait to change her diaper until after you've fed her on one side, then change her (it will wake her up), then switch her to the other side!