I wish I could reach out over the internet and give you a huge hug @iamkjx.
I hear you, and I could have almost written your post (DS was premature, almost born at 26 weeks in lockdown, 7 weeks of hospital admissions on my own layer, he was born, in NICU for 2 weeks). For us, it's been so hard, as he was in the newborn stage for over 3 months (didn't smile until he was actually 3 months, but 6 weeks adjusted).
I completely echo about being able to form a support bubble after this lockdown (thank you Mumsnet, I found that out here, going to form a bubble with my DS, BIL and DN).
Likewise, with the PTSD and postnatal anxiety/depression, I've finally reached out to my GP and health visitor, and they have been wonderful. I've got an appointment with a local support group (Bluebells) in person, one to one baby massage classes, a referral to the perinatal mental health team and a telephone appointment with talking therapies. Please, try to talk to them.
I've found that (boring though it is) going for a long walk every day gives some structure to the day, although it's a challenge sometimes.
I'm not on Facebook, but there are lots of groups out there for support too.
Some parent and child groups are still running, under the umbrella of being a support group.
For baby socialisation, it isn't the same, but there is a baby program on CBeebies, (Baby and me?), that takes the form of a videoed baby group, with parents and babies in a circle, and singing and sensory activities. I've started to watch that with DS (almost 6 months, but 4 months adjusted).
Also, sounds silly, but I've kept a notebook through all of this, and written down how I'm feeling, and what is going on in the world. Out babies will be part of history now (I guess like those in the World Wars), and I wanted to be sure that I could record for him what life was like. I like to imagine that in 100 years time, someone in my family will be doing a school project on what like was like in the 2020 pandemic, just like I read my great grandmother's diaries.