It’s hard. And I see that you are in a bad place and not ready for practical ideas yet.
But when you are... You can find local baby groups and make friends WITH your baby. People with the same restrictions as you.
You can find mum and baby gym classes where you use your kid as a weight.
You can get adult interaction virtually, online, here.
I was a single mum with a demanding job and absolutely no support from when my son was 2 until 6. It was hard. Bloody hard. And demanding. And lonely. And scary. I got a good childminder but that was all I could really do to lighten the burden.
But they were also the best years of my life in many ways. Me and my son are incredibly close as a result. We went on loads of adventures together - we had to, I couldn’t leave him anywhere if I wanted to. We took up a hobby together when he was older. We had an amazing time. And when he was in bed I lived online.
Now I’ve remarried. I managed to date when I had made local friends to babysit.
It all seems scary because you’re trying to solve every problem, all at once. You won’t have to do that. A step at a time.
Good luck. I do know that it’s worse being lonely in a relationship, than out of it.