Tax help!!!

So my husband made a little more for 2019. We aren’t legally married but we’ve been filing Married Filing jointly. So this year the numbers went down even tho we claimed our child. So I try doing it just me with my child and the number were up, and with my husband alone and adding the numbers together we will get more back by filing separately. But for some reason when I file us together it goes way down. What should I do in this case?