Worried my boss will be angry

I left the heating on once before last week- before closing up the shop- and I think I did it again. I can’t sleep now, my boss said he’d get rid of the heating if I did it a second time. The first time I did it I was tired and did a ten hour shift and completely forgot, I forgot yesterday because I was rushing around- I wasn’t the last person in the shop/ locking up so I hope my coworker noticed. I feel like an idiot!

Any advice for what to say if my boss is angry about it??

I agree with the other poster. We are all human and mistakes happen.
If need be explain to your boss, and assure them it wont happen again.

How did it all work out anyway?