Baby Gasping for Air??!!

My baby is 6 months old and has always been a little noise maker. She used to inhale air that sounded like gasping while she was awake. Pediatrician said it was normal since she was starting / trying to talk. She no longer does that.

But since she got her vaccines 2 days ago (8.25.17) Shes been gasping in her sleep. Its only a few seconds long, but she's never done it before (while sleeping). It worries me and I'm going to call the doctor tomorrow (since today is Sunday).

But my question is, have any of your little ones gone through this? Have they outgrown it? I need some reassuring because all the articles I've read don't do any justice and just makes me worry more.