Is it supposed to be this hard

Must be so hard for you and especially in a really challenging time in their lives! Unfortunately, they are learning to push boundaries which is developmental.
From my own personal experience we introduced ‘time out’. I did a lot of research on this because I didn’t want to start something that wasn’t going to be effective. We use time out for situations like hitting, being shouted at etc. it should be a minute for every year that they have been here - currently doing 2 minutes for our 2 year old. It doesn’t come without resistance but we find that she can generally tolerate a 2 minute time out. Once completed, I get down to her level and explain why we can’t have that behaviour, have a cuddle and then she can carry on.
Have you considered reaching out to your Health Visitor for support/advice? Is LO in nursery or do you have support around you so that you can have a break?
I’m so sorry you’re going through this, please feel free to message me if you need to chat!🤍

I’m so sorry you are going through this, you must be exhausted. To answer your question, yes, it is tough! Us mums are tougher though but we can’t do it alone. To echo Morgan, please reach out to the HV for support as they will provide it if needed, you don’t need to do it alone.