Working tax credits and carers benefit advice needed

I'm confused as to my entitlements and have been turned down for tax credits I just wanted to check that this is right

My basic info is
Husband works 45 hours week
Me 9 hours
Get carers allowance for my poorly mother
Have twins starting nursery

I have been told I'm not entitled to working tax credits as I don't work enough hours but can't work more because of care is this correct ? Please help !