Fuck they really are despicable. I reckon THEY are shit scared of it getting out that they did that to a pregnant woman - not many people will want to associate with someone who is capable of doing that.
I was bullied for years, and was like you until one day, I realised that I held the power over them - if I came across them, I could easily tell everyone that knows them what sort of people they actually are. What they are in my case are people who found it amusing to physically abuse someone who had been sexually abused at a VERY young age, had their father kill themselves when they were 10yo, and was being physically abused at home by an alcoholic parent.
That makes them scummier than scum.
There WASN'T anything wrong with me, other than the misfortune to be born to an alcoholic mother with little regard to her boyfriend's preference for 4yo's and a father that had been sexually abused himself and couldn't deal with if, and the sheer misfortune to end up at school with some fucking warped bastards.
Once I realised that it was ME that had the power to demolish THEIR life if I told anyone they knew what they were really like, I wasn't bothered by them any more.
Now, I have actually come face to face with one of them, and when she gave me that 'look' that years ago would have me feeling inadequate, like I was less than the shit on her shoe, I just looked right back at her like that, and turned and walked away. One of my other friends said that the woman went pale!
I never DID tell anyone, because I'M not in the business of destroying other people's lives, I leave that to the sicko bullies. But it felt good to know that I could but that I was better than that IYSWIM. It was kind of like an 'insurance'.
In your case, it's SO extreme, that I would tell one or more of the mums that you are getting close to, and explaining that because of the systematic abuse that ended in them running a car into you whilst you were obviously pregnant, you feel scared around them.
Any decent person will be so
by what they did that they will do their best to protect you from these people.