Wow, what an awful night for you. Let’s hope you get some good direction from the specialist nurse today because you surely don’t want a repeat of that episode.

Have you had routine headaches since starting the HU? Make sure you jot down how often this occurs, if you can think of any triggers such as food, allergies, etc., besides the possible connection to the HU. Seeing that there are others in the forum who have had experience with the headaches it doesn’t seem uncommon for that to happen. However, there can be changes made to lessen the side effects.

This comment from @ontheverge today was timely…with their comment on headache with HU.
https://connect.mayoclinic.org/comment/897146/
Good luck today! I’ll be thinking of you and fingers crossed for no headache!