you need to tell them if your working or changes in your hours, but I think it shouldn't effect what you get now, as the figures they use are based on the previous years earnings.

but you will get less, the more you earn the less you get in tax creds

i've no idea how they work it out, but what i get goes down each year, even thou every cost more

depends on what your hubby earns and what you would earn, but if you've got to pay for childcare and you're earning too much for the child care element of tax creds, see if they have a childcare voucher scheme at your hubbies work, that could save you a bit and where you work