I have problem with my rancher installation:

1. I had to upgrade Amazon EKS kubernetes version through Rancher UI inerface from 1.12 to 1.13
2. Then I followed this: https://docs.aws.amazon.com/eks/latest/userguide/update-stack.html because all worker nodes in the cluster had the old kubernetes version
3. The upgrade according to Cloudformation interface went well
4. All nodes from Rancher UI cluster view disappeared and all my services became unavailable

I'm not Rancher or kubernetes master obviously. And I have no idea why it went wrong. What should I check?