Becoming a SAHM tips

I got confirmation today that I don’t have to pay back any leave health benefits so I won’t be returning to work after my maternity leave is up! I will have a 2 year old and a newborn. My 2 year old will continue to go to daycare, but part time instead to continue his learning (he really loves going!). I have never not had a job so I’m a little worried about how I’ll cope staying at home and doing the world’s toughest job! Any tips for me? How do I stay sane?