I know the feeling all too well. I'm a nervous nelly too! Before you gave her the treat today, was her stool normal? Can you show me the brand and style of treat you purchased? Just to let you know there are those with sensitive tummys. One off schedule type treat will make their digestive system so upset.
I suggest keeping on the chicken meal and make sure she gets lots and lots of water.
My girl sometimes breathes fast and shallow when she is lying down napping...its just something they do.
When Sheba had bad poopy I gave her chicken and rice and she gobbled it up and her potty was really good the next day. Eventually changed over to grain free and things were a lot better for her.
Keep an eye on your girl as I am certain you always do and things will work out just fine. As always, see your vet if you have any feelings of uncertainty.
Oh, and be careful what you read sometimes on the internet. There are too many opinions and stories out there. Give her lots of love and ensure her that she's going to be fine! She'll kick it for sure! Sheba and I send our hugs and kisses too!