Have you taken legal advice?
I only ask as a friend had a very similar thing happen, if it wasn't for how old your DC was I would think you were her.
In her case, she is a single working mum, no concerns about her, not so much as a parking fine. Great relationship with midwives and health visitors.
Her eldest was 6, (this is 5 years ago now), youngest was 8 months. She and ex split up whilst pregnant with their second but on good terms.
She used a childminder. Picked up child, youngest was very upset. She said the cry was nothing like she had heard before and she immediately knew something was wrong, but not what. Childminder denied all knowledge.
On lifting the child up, he screamed, she said it was obvious pain, and was doing so when she touched his arm
Again, childminder said no incidents.
She put both in the car, and went straight to A+E, the baby had a fractured arm.
Same happened, not allowed to walk out the hospital, police interrogation. 8 year old said the childminder had a child in their care who was horrible, and had "whacked the baby hard and pulled his arm".
Despite this, the childminder denied all knowledge, said she had an accident plan, said the baby wasn't crying in pain when he left (utter crap), and got away with it all.
She went through this for 18 months. They would turn up at her door unannounced. They raked over the breakdown of her relationship. They got so many statements listed as fact that were utter shit, in one situation they said her mum and dad had put her in foster care as she was a twat away teen- it later transpired they had mixed her up with a girl with a similar name.
She felt like you, under the microscope. They made constant threats to remove the children in fact, the more she disproved the nastier they got.
I remember her crying her eyes out when I went to see her, as I had written a statement of support as a character witness. She ended up on medical leave and they used that against her too.
Then just like that, over. A letter saying we have concluded our investigation. No apology, no "we got it wrong". In fact it was more "we can come back at any time".
6 months later, she got a knock at her door, they were doing a random check. It was pure intimidation. So she hired a solicitor. She successfully sued for harrassment, for the false statements, for the intrusion. They settled the case out of court. During that time though, the childminder was found to have been in charge of a child who later suffered another serious injury and that time she didn't get away with it.
So you can, and you should sue.
And I would speak to the doctor about counsellor.