Test for Covid. Let guests know. This happened to our neighbor's son. Turned out he had RSV. A bunch of people cancelled (we did too because our daughter was alreary sick) but a lot of family still went. Hopefully their kids were already immune or got mild cases.
I wouldn’t cancel, I would postpone it to next weekend.
Happy Birthday 💕 If she feels/seems worse then maybe just postpone the party if possible. It would’ve been better too if you ran your daughter to the urgent care today or booked a same day appointment just to make sure it’s not anything serious.
We still had our daughters party today and she is the same way but I told all guest and let them decide if they still wanted to come