I'm an illustrator. Can I say "I'm fully booked" to mean that my schedule is full?
I've always heard the booked verb applied to "performative" professions: Models, event planners, singers, etc. Never for pure service and creation-oriented occupations as on-site technical support providers or painters. You book a model. You don't book a writer.
If this expression isn't appropriate, how else could I word that "schedule" sentence without being so passive or mouthful?