The sentence should be "I'm worried about any more slacking off." I'm not really sure about the context but one scenario I can imagine is a teacher speaking to his students it could mean that the students didn't do some classwork before the time of speaking, so the teacher is worried about them not doing the work in the future. It could also be a boss speaking to his employees, or any similar situation, but basically the person speaking is worried that the person (or people) they are speaking to is going to slack off again (they haven't done something they should have in the past). Hope this helps. :)

Hi Susan, I assume you are reproducing something you were listening to? In that case the person was probably saying: I'm worried about morale slacking-off. Slacking off means that the level of standard of something is dropping. So in this case it means that the person is worried that the level of confidence dropping (morale basically means confidence or enthusiasm). I hope this is helpful? Regards, Shirley

Dear Susan I think, finally, the sentence should be "I'm worried about moral slacking off". Morale is positive spirit: optimistic, active people have high morale; passive, pessimistic people have low morale. The sentence is something a leader might say of a group they are leading: they are worried that the group's morale might decline (slack off).

it means that you are sorry for not being your best

I mean morale slacking of sorry