So I just wanted to update everyone on what's been happening with her. I kept an eye on her all weekend and noticed that she only pants when she's in my room. I have a mat in there that she loves sitting on and she's always panting when she's on it and her beak becomes very warm. In the living room, she's perfectly fine - steady breathing through her nose. So maybe you guys were right about the heat getting to her.
The only things that are still bothering me are the whistling sound that comes and goes, the occasional sneezing fits and her opening her mouth like she's gagging(?) and scratching the underneath of her beak when she does that. Could that be the respiratory infection Saaniya mentioned?
Remove the mat and let her stay in cooler place if she seems very warm
And where she gets plenty of oxygen like near window
It's important to give them fresh air especially when they are indoor pets
If she sneezing while eating or drinking i didn't look for worry
I will simply change her feed and try to clean the dust or dirt
Second I will add some 1 drop of oregano oil in 1 gallon water and give her for a day to cure any mild RESPIRATORY Issue
Third if she's acting fine eating pooping drinking I don't worry just change her place
Respiratory symptoms Exist then I do Antibiotic
I agree with other posters in that she’s probably just hot. My Pekins get hot way before my cayuga ducks and my cayuga ducks are black.
I have sat and listened to my ducks while they were resting and sleeping before. I noticed several made a wheezy sound. I started to get worried but as I watched them, they acted completely normal. So as long as her activity is normal, I wouldn’t worry.
) but she doesn't seem to have any issues. It's just that wheezy sound like you said. 
I think she's okay now. She's still whistling and sneezing a bit but it's a lot softer and doesn't seem to bother her at all. I've been using the oregano and she's doing well on it. As long as I keep her off any warm bedding, she's a happy, healthy baby. 

