Probably over reacting

I'm seriously about to go insane here. My husband and I are both self employed so we are always very mindful of money and spending cuz we make basically just enough to live on. Our daughter just turned 1mo and she's 7lbs.

About a week and a half ago we ran out of new born size diapers. Well dear husband has decided that it was too much money to go buy more newborns and that we should just use the size ones because they start at 8lbs. Well I work at home so I'm taking care of her most of the day by myself. Well baby girl is small and the diapers are a little big on her and if she wiggles the right way during the day they leak both solids and liquids which usually end up all over her, her clothes and me on a daily basis at least once.

I'm getting so sick of getting pissed and shit on its not even funny. He just keeps saying that he's not getting anything on him so he doesn't know why I'm having such an issue.

We only have one car and he usually stops at the store to get groceries on his way home and obviously refuses to by more diapers cuz he doesn't want to spend the money just because of a slight inconvenience. I'm literally about to go insane! I'm probably really over reacting but I getting really sick of having to wash poop out of onesies and changing her and myself more than twice a day. What are your thoughts???