I need help / advice

Al

I have a newborn and a 2yr old well my 2 year old has been driving me literally insane I have no patience for her at all . Since we’ve been home w newborn baby ( 3weeks ) she’s not listening anymore she’s yelling / talking back hitting us she sticks her tongue out and spits at us when we tell her no or to stop doing something and the icing on the cake lately has been at bedtime she refuses to lay down she screams and cries as if someone is killing her if dad tires to console her she screams even more . I breastfeed baby so he’s pretty much attached to me from the minute we come to the room so I can get him to bed which makes her scream even more . When she finally does fall asleep it doesn’t last long before she’s awake again screaming crying for who knows what . We just introduced melatonin to see if that’d help and it’s fine nothing for her but seem to make the tantrums at night worse . Her screaming and crying wakes baby so I’m back and forth with trying to get her to stop and getting him to bed which causes even more crying . I’ve broken down twice tonight cause I’m so tired of so over it I’m so frustrated and annoyed . I just don’t know what to do anymore . Someone please offer some advice on what I could do to help .