Help needed for me and my son

Hi, I am looking for help. 

I recently become widowed when my husband died of pancreatic cancer, leaving me to bring up my young son on my own. 

After he passed I began to find out that he had been keeping secrets from me, secrets of debt and lots of it. I had found out that he hadn't been paying for the mortgage, had got a £12,000 tax bill which i am liable for now. He had been getting letters from the mortgage company that they were starting the process of taking the house from us and was hiding them. Because of this I had to sell the house and leave the house where my little boy was born, it was heart breaking. 

Now I find myself struggling to pay the tax bill, pay the rent, pay for child care so I can go to work, even general day to day expenses and I'm finding it so stressful. I just want to pay off his debt and the few credit cards I have (used to keep me going, by now at their limit) and start being able to enjoy life again and concentrate on my son instead of worrying about money. 

Any help would be sooooooooo appreciated.