Ok I’m head of household It’s only me and make under $40,000 a year I always receive a refund but yet this year when I finish they say I owe them

Trying to figure out how in the world I would owe them I have a mortgage taxes on my house I pay bills just like everyone else and it’s just one of me so trying to figure out how that would equal out to me owing Vincent money something is going wrong here I also was one of the first people to fill out my taxes and still haven’t received a stimulus check so I’m concerned and afraid I may not even receive a stimulus either I live here in Alabama and we don’t really have a voice so I’m trying to figure out what is going on with the government at work hard pay my bills so I deserve my reward Which is my tax refund because I don’t make enough money to display I don’t think so that’s where I buy the things I really need