My baby is having breathing spasms in her sleep.

My baby is three months old and tonight she had her first long crying spell. We got suck out later than intended and so her night time routine was completely messed up. She didn't end up getting in her pajamas and going to bed until a few hours after she normally does. I tried everything I could think of to get her to stop crying, eventually (after what was 20 minutes or so of heavy sobbing) she finally fell asleep while I held her against my chest. She's deep in sleep but it's been ten or fifteen minutes and she's still having these breathing spasms, like one would after trying to catch their breath after crying. Should I be worried? Is there anything I can do? How long will this last?