My website was down after changing nameservers to Cloudflare, so I switched back to google Nameservers and it came back up an hour later. I just switched back to Cloudflare to see if it does it again. Is it normal for a site to go down during the switching phase to Cloudflare?
It depends on always from your registrar and the time that is necessary to update the nameservers.
Did you wait also 1 hour when changed to Cloudflare?
Check our documentation:
If your domain is particularly sensitive to downtime, review our suggestions to minimize downtime.