I just had a dog that past away over thanksgiving. How do I help my other dog cope wit the loss?

My dog that ped away was an english mastiff. We had to put him down for kidney failure. That was just before thanksgiving. We have another english mastiff thats 4 1/2 yrs old. She isnt taking it well. Shes never been away from him, not even for an hr, since she was 8 weeks old. Well heres my problem, shes driving me crazy, always on my tail now. She follows me everywhere never leaving me alone. Now I know she needs to greave but heres the deal, I'm pregnant due any day now and I'm worried what will happen when I bring home a new baby. My husband thinks I just need to be more firm but I dont want her more upset, shes real sensitive. What can I do? What should I do?