Laughing at pain

Ok I really sound like the worst person ever but I was brought up to laugh of my pain example if I fell over go ah well stand up and chuckle to get over the pain. But now I'm an adult and a mum I find it so hard to control it and I feel like the worst mum in the world because when my daughter trips I'll laugh if she's hurt I'll run over soothe her and try make her feel better but I'm still smiling/chuckling. My OH gets annoyed with me but I physically can't help it I've tried changing my train of thought like she may be really hurt or falling over isn't funny it can really hurt. I feel awful all the time and I don't know how to stop it.