Regretting having a baby 😩

I am scared like beyond scared, I’ve got a 5 year old son who doing great, behaving well, growing up so fast. Me and my partner decided it was time to have another baby as we’ve always two children 👶🏻 since being pregnant my son has turned into the devil , his behaviour is shocking and I don’t think I’m going to be able to manage once baby comes along 😫 discipline isn’t working, I’m at my wits end and very stressed which isn’t good while being pregnant. I’m 27 weeks and I’m dreading my due date coming as I don’t think I’m going to enjoy being a mother to two anymore with how terrible my son is behaving 😫

I need advice, has anyone been through this and it turned out okay??