Congratulations on your pregnancy. Your feelings of shock and anxiety are completely normal! I was looking forward to a nice, easy pregnancy and sibling for my eldest as a second time mum- never planned to have three. I didn’t really enjoy my twin pregnancy as I was so anxious about how we’d all fare through pregnancy and childbirth, and managing afterwards. I had 3 under 4, so not quite as much on my plate but still a challenge.
You’re having fraternal twins which are the lowest risk twin pregnancy. I also had DCDA twins, scheduled scans every 4 weeks but ended up having more in between- be prepared for lots of hospital visits.
I had mine at 37+3- which is classed as term for DCDA twins. I attempted a vaginal delivery that ended up in an episiotomy and double forceps birth. Babies were 7lb 1oz and 6lb 5oz and we were all discharged after an overnight stay, no special care needed. Both babies healthy, biggest one slightly jaundiced but that cleared. Lots of twins are delivered by section, but a good few are vaginal or instrumental. It will depend on the babies’ positioning/previous deliveries/pregnancy complications whether you attempt vag delivery or straight to planned section.
In terms of coping with the babies- I was absolutely dreading dealing with two newborns but it wasn’t as bad as I imagined. We mostly formula fed so I could split nights with DH- my eldest still won’t sleep alone so one takes the babies, the other takes the 4yo. If your older children are in childcare it’s a good idea to keep them there if you can afford it, as the babies take up a lot of time. The isofix car seats that clip into a frame are great when the babies are little- you can probably get a buggy board for 22mo. Logistically everything takes longer- mine are big boys so I can only carry one at once, but provided you have a safe place to put them it’s all fine.
If you have a local twins group it’s good to pop along to that- the mums there all understand the unique challenges of twins.
Mine are nearly 9m now and I love having them in my life, I’m so glad at how things turned out (definitely done with kids now though!). Not saying it’s easy, I find the baby stage so hard but I would think that if I only had one too.