Sign in, look at your dashboard, if there is anything that needs attention, it would say it right there, also you would get reminders by Airbnb that something needs your attention and you need to answer. Who knows what it was, most likely not a booking request. You might also check into your listing via your desktop or lap top, maybe you'll find something in your message folder then.
First image to show when you click dashboard:
PS : Oh what a great place you have!! Great photos also, but I still would like to see the main bedroom and the tub or shower in the bathroom. Considering especially how wonderful your place is, I would put tight house rules into place, start with the ones you just click on/off on the platform Airbnb offers for house rules, then add your own in addition.