To teach all day for £11.90 p/h?

[Sooooootired01]

I'm a qualified teacher primarily working as a SEN HLTA. Pay £11.60 an hour. OK I guess.
Last week I covered for a teacher who had gone on residential. This meant teaching all day from Monday - Wednesday, a full and routine curriculum of English and Maths etc. 30 kids in a class, no supervision, completely left to own devices. Again, I'm qualified so fair enough. Lessons preplanned but of course still needed delivery.
AIBU to think that paying me rate of £11.60 p/h for this is not OK?

Do you actually manage to take your breaks? I never got an uninterrupted paid or unpaid break.

@ChangeAgain2 No, never. There are always kids sent in or staff wanting informal meetings.
I've started to go for a five minute walk when I can escape just to catch my breath!
The other day I was genuinely in pain as teaching from 8.30 - 12.10 and on break duty with nobody to cover so I could rush to the loo (probably doesn't help I'm perimenopausal!)