Help! What can I expect while expecting?!

Hello, I am a single mother of two children. One is a special needs 6 year old and I have a 3 year old as well. I am also expecting baby number 3. The man I am with and I have been together a few months shy of 2 years. At the moment he lives with his parents as do I. We lost our house last year after an extremely difficult time in our lives. The father of my oldest child is absent. My 3 year olds father is deceased. As of right now I take care of the children. Alone and spend most days alone as well. My boyfriend works manual labor usually from 6:30 to about 4 or 5 pm daily. Usually he comes to visit me and the children once a week on the weekend and on holidays. I am a high risk pregnancy of about 16 weeks right now. I never get a break from my children for even a nap and no one has ever offered to help me. My parents are amazing and I am grateful for them allowing me to love here but they can not take on my children to help me in that way right now. I have been so fatigued as well as constant nausea and throwing up. My oldest child has behavior problems as well as blindness and requires an extreme amount of care. I have asked my boyfriend to help me out and I have also asked him why he always spends his time off of work staying at home. His response was that he had a hard time handling my children and that he wanted to go home and relax. Usually he goes home to sleep watch Netflix or play on fb. When he does see us I do not see any effort to spend bonding time with the kids and for example if we are at a store and the kids run from me in the parking lot he will just watch and let me run to go get them. I feel very alone and have made this clear to him. He tells me that I am expecting things that a husband would do and that it is unfair. He says he works hard and will sleep when he wants to. Although I never get a break or any rest. I am very unsure of what to expect from him with my children and our relationship right now. Please any advice would help.

Are you taking any kind of birth control?