Hi op. I totally understand feeling super scared! My good friend who this happened to with her second cried for three days. They are a happy thriving family of 5 with 3 elementary schoolers now. Those early years were hard, but you will do it and you can. I would join twin groups as you'll really get the best advice from people who can truly understand what it is like to have twins. But a couple things: do consider a night nanny! Sometimes throwing money at some things early on is worth it.
And, I just wanted to plug that it might be worth it to pay for a sleep consultant once the babies are 4-6 months. Since you didn't sleep train with your first, having support could be crucial. In particular, sharing that I used a consultant through The Peaceful Sleeper and as someone reluctant to any sleep training but with a situation that needed it, it was a great fit so I wanted to share. They truly can adjust to people's needs, wants, and how gentle you want to be. It isn't a one size fits all. Having the consultant walk us through (we did one of their group ones where they were with you watching the monitor with you) was worth every penny. Maybe you'll get two miracle babies, but more likely you will need to do some gentle sleep training to keep you all ok.
https://thepeacefulsleeper.com/