Please help, 7 weeks pregnant and so sick, I can't do anything?

I'm 7, nearly 8 weeks pregnant and I can't do anything. I have constant nausea and if I even drink a few sips of water I will vomit that up and then my stomach will still keep heaving even though it's empty. I've tried everything, eating small snacks, eating before I get out of bed, not eating at all, it makes no difference. Added to this I'm so tired all the time, it is literally an effort to keep my eyes open. I'm usually very energetic and take my son out places, play with him, cook and keep the house spotless, I literally can't do anything but lay in bed with my head in a bucket. My husband can't do much around the house as he works shift work and I don't think he quite realises how I'm feeling. I have no family to help and cannot afford to hire anyone, what do I do? I feel like I can't go on like this I am completely miserable. If anyone has any advice I would appreciate it.