Feeling sad?

Im so excited about my pregnancy but at the same sad getting really depressed about the atmosphere in which im going to have to bring up my child, i lived with my mother and my little sister and brother and i was fine there but had to move out because there wasnt really any room for me so i had to move to my grandparents, i love both of them dearly but i just dont have a great relationship with my nan she can just be so vicious sometimes and it doesnt matter what i do i can never please her or even get a smile from her its as if she hates me, and she just causes me so much stress im scared that when the baby comes its just going to be too much and ill just brean down, shes the kind of woman that will probably accuse me of pushing my tummy out when i have a bump because i "shouldnt have one so soon" and be calling me a drama queen for wimpering even once in labour, not only that but the house is just so dirty, i mean you wouldnt walk in and think omg but they have this scruffy old dog that constantly scratches and theres dog hairs everywhere! In the air for god sake! Its on me 24/7 when i get out the bath it lands on me, its on the towels, its always in my food! It doesnt matter how many times i clean the house! Im sorry for ranting and i doubt anyone will understand but im just praying i can find a place of my own before the baby comes i really dont want my baby breathing in dirty dog hairs and my nan constantly interfering and telling me im bad mother and im doing things wrong?