DD sad about being hit at pre-school? What should I do?

[puffling]

Toddler DD has been saying she doesn't want to go to pre-school for this last week. She's not been like this since the week she started in September. She says her friend has been hitting her and described what happened in detail. Obviously I can reassure her, ask pre-school to watch out for her etc. but I can't bear to think of her feeling miserable about it. DP feels she needs things like this to learn about life and will need to learn that she should defend herself by hitting back. I'm not entirely convinced of that.

What can I do right now to reassure my little girl and help her be confident in situations like this? Any advice on good parenting books would be appreciated too.

Thanks for advice Loopymumsy. It's her best friend, who's always been like this to her. They are fond of each other but the bf does really enjoy getting a rise out of her. Her mum is aware of this as it happens when we're all together but obviously we don't see what happens at pre-school.