OP, it sounds like your relationship was on the rocks for a while. In the long run, being with your exDP and a baby would probably have worked out worse but he is being really horrible to his unborn child, leaving you to struggle like this.
I wondered if you know his family? Maybe you could contact one of his close relatives eg parent and ask if he’s ok, say you had a bad break up but his behaviour is worrying you. His baby is due in 3 months and you wanted to talk about contact, finances, that if he doesn’t get back in touch there is no chance you’ll want him at the birth after he has blanked you for months and it would be a shame to miss that if he has any idea he might want a relationship with his own child.
The emotional turmoil this has caused is making you think you can’t cope with the practical side of things. I’ve been there - feeling overwhelmed and out of control. So many things to do and no idea how you will have the energy to do them.
Break your problem into small pieces and each one accomplished will make you feel better
I think you should plan to move - but not immediately after the baby is born. Ask your family to set aside the inheritance and only pay it to you in instalments when you ask for it.
ask your midwife about local baby groups, and do attend a prenatal group. NCT might run a Bumps and Babies group locally so you can find a friend or two, and lots of churches have a free mum’s coffee morning (and I’ve seen some dads and grans there too).
your LA will have a list of childminders local to you online most likely, you can start calling to find out when someone will have a space
ask your employer if you can go back to work part time after 6 months and/or compressed hours and/or wfh
Do not start mat leave early unless for medical reasons. I know ladies who have waddled around til their waters broke at work. Keep your maternity notes and hospital bag on your car so you’re ready from 8 months.
Ask your Parents or siblings or even exDP’s Parents for help in the first month after baby is born. Tell them you are desperate. Ask if they can help with getting you home from hospital, staying for the first several days. If everyone rallies round they could each take a day or two off work and help you cope with the practicalities of being home alone with a newborn.
Start saving like crazy! Try not to buy anything brand new for baby - if you have siblings they may be able to loan you maternity clothes, baby clothes, bottles, cot, baby bouncer, pram, blankets, sling, breast pump. If they can’t try FB market for second hand stuff or bundles of clothes on eBay or Vinted.
And look for those little moments of quiet and joy - take the time to stop and “be” with your bump. Put on nice cheerful music, dance and feel the baby kick. Go for a walk in early morning sunshine and just… breathe.
It is sometimes terrifying thinking what lies ahead in your parenting journey but I can tell you that even with lots of bumps in the road, I wouldn’t change a thing - my kids are the best thing I ever did and the love, fun and joy they bring is invaluable. So much more than I ever expected. It can work out fine OP. You’ve got this.