dear me. you are n o r m a l. you should have heard my then next door neighbour screaming at her three as she bathed them ready for bed every night (in the 1980s). screaming. night after night. and she was a wonderful mother. i mean that.
recover the presents from the bin, even if you don't tell the children yet. you wouldn't want to spend the money again.
get the children into bed, or their rooms (you don't want another fight) and have a brew.
after your cuppa, think about what you do want from your children, in the way of behaviour.
write it down.
spend tomorrow thinking it through.
tomorrow night, think about how you're going to get it. think supernanny - though for me, i'd never be arsed with star charts. but clear boundaries, expected behaviours, 'punishments' which are meaningful in that they let the child know they have done wrong but can come back from there...
write it down.
when your ready, explain it calmly and firmly to your children. they'll try it on. stick to your guns.
you're doing this on your own because you parent on your own.
when your husband is around, explain to him and tell him you expect his support. he might try to undermine you. if so, privately pull him up on that. you have to do the childcare, you make the rules.
you can do it. you brought them this far.
good luck