
Don't cross your bridges before they're built! Are you sure yet that she's pregnant? Your vet should be able to scan her at about 28 days (though there have been dubious results from this) or x-ray her at about 6 weeks to confirm pregnancy. You wouldn't be increasing her food or altering her lifestyle before this anyway. And the vet is the best person to ask for worming advice - there are many different products available, with to be used at different stages.
Hope this helps.
:)