This is hard 4 kids

So my kids are 1 2 and 3 and I have a newborn lucky I have the kids dad to help he takes the boys and I take the girls the 1 year old and the newborn but this is so hard I already had a two breakdowns I’m so shaky and I don’t know why I’m struggling to breastfeed and give my kids attention I feel bad for my boyfriend because he’s always with the two toddlers it’s just a lot any advice