To file jointly, or head of household for biggest return? Im a s.a.h.m. with 3 kids, very low income this year?

Im confused because i keep reading to file jointly. However previously we ALWAYS filed with him head of household. He made around $59000 previously and we always had a tax return amount of $3800 back to us. Now this year i did the whole tax thing online, with filing jointly.. just to see how much the return would be.. well it said only $1600! Im VERY confused by this. This year he had a bad profit in business and made only $47000. Plus we still have the three kids, im very confused as to why it was such a dramatic difference?!!