Feeling like I'm a single mother

What more can I say? We've been together 5 years now but I feel like things are changing... We have a 3 year old together and I never minded being Mommy and caring for my son's needs but now that I'm about to give birth I'm finding myself more annoyed by the fact that my other half isn't helping me enough.. my son has been getting up constantly throughout the past going on 5 nights and dad is just fucking sleeping away.. I cried and asked him for help literally saying please I'm exhausted and tired and he got angry and still slept... Wtf do I do I'm losing my mind and my worst fear is coming true id hate for him to do this when our new baby is here and he's just not understanding why I'm so upset and hurt