This is still so raw...it's not going to get better overnight lovely.
It's hard, but trust me, you will be ok. I remember, as I'm sure others do, the devastation left. I felt like my world had imploded and had no idea how I was going to get through without him. The first few weeks after, I can't even remember to be honest, I have no idea how I got through everyday, but I did.
BUT...once the shock subsides, you will be practical. Get your tax credits sorted and find yourself a solicitor.
Spending time as a family, as much as you want to, is not a good idea, and I think you know that. I know your hurting, and you want your family back, but as of this moment? It's not going to be the way it was.
We are all here to hold your hand through this time. He has been awful to you, he has left you and your child, your home, your life together. Get angry...it's motivational, will help kick your brain into practical/survival mode.
You are going to be ok....there will be a time when you'll look back and be in awe of how well you did, how much of a better place you are in.
A day at a time, that's all you need to focus on, look after yourself. I lost myself in making sure the kids were ok, and while a marriage breakdown is a great way to kick start a weight loss program...the fast weight loss and dehydration didn't do me any good in the long run. Small things...drinking water, a slice of toast...a mcdonalds with your child.
Huge hugs