Oooooh, this is so tricky. I see both sides.
I'm sorry you having been ill and struggling with your mental health @Gonnagetgoingreturnsagain and I wish you well, but yeah, the hairdresser is not in the wrong here, and she was right to be annoyed that you didn't show again. (I appreciate there was a good reason the first time.)
As several posters have said though, they really do need to find a system that automatically texts a reminder (like the GP/NHS/Dentist/Opticians.) They would get much fewer no-shows then. My hairdresser is the same, they give me a little card with the appointment on it (if I book it in the salon,) and that's it. If I book it myself I have to put it on my Google calendar immediately or I will forget! 😬
I agree with the poster saying you should offer half towards the next appointment in advance. As a goodwill gesture.... Seems like she calmed down after a while as she said 'don't worry about it' later on.
Try not to get worried or upset about it, I am sure she has had people not show before, and had a mini moan at them.
Just get her some flowers and pop in and book the next appointment, and pay half towards it. (AND PUT THE APPOINTMENT IN YOUR CALENDAR!!!!!!!'
Enjoy your Easter break.... 