Why is my mum always in such a bad mood?

My mum always seems to be in such a bad mood. Everything me or my little brothers or sister or dad do makes her annoyed which usually causes a mive argument and she doesnt speak to any of us for about a week. Its not something that shes just started its happened for so long. Its ment that im really not close to her and dont really feel comfortable speaking to her about things a normal teenager would. When shes in a mood she just sits there watching tv and wont do any cleaning or washing or cooking and ignores us when we talk. I try to be as nice as possible to her to stop the arguments but it always goes wrong. Were moving soon because she gates living were we do atm so she should be happy. The arguments are always over the most stupid things like not setting the table at lunch or putting clothes in the washing basket, our bedrooms always have to be spotless and were rarely allowed friends over. I thought it was maybe cause of her period but she cant get it that often and its not menopause cause shes only 37. It just gets really upsetting for us all and we can never do things as a family.