Ok, can you tell me if this is fair?

I am 14 years old, I have a brother who is 16 and a sister who is 8. I have to do ALL the cleaning in the house because my mother is a lazy betch and my dad works all day. I just had a baby 1 month and 2 weeks ago, so I need to worry about taking care of her, not cleaning the house 24/7. My mother literally just watches T.V or drinks with her friends. She doesn't make my sibs. clean, only me, when I should be taking care of my baby, I understand I need to help out, and I don't mind, but like I said, my baby comes first, always. She buys the babies food(the formula) and I buy the rest, and if I say no to a chore she says she won't buy her food, I buy everything else she needs(clothes, diapers, bibs, pacifiers, her crib, changing table, dresser, ect.) So, what do you think I should do? My grandfather already told me I could move in with him and his boyfriend, but I don't want to feel like I am barging in on their lives.