Well it doesn’t seem to be so slow. It did 1.5s first view (1MB total) from a server 1000 km+ away with no local cache in the POP and 250ms repeated view with everything except for the base HTML cached in browser memory.
Successive repeated views with cache in the POP do 0.6s, it’s really quick!
Where is your origin located? It may be that Cloudflare’s POP near the service has not a cache of the page and needs to request it adding latency, a repeated view may solve the issue.
Well, check the IP, it may be yours that simply changed due to a modem restart/reconnect.
It’s a wordpress site, known for being a bit slow. You should cache the page w/in wordpress using a plugin like CometCache (preferred) or cache it on CloudFare.
It isn’t a given that the cache is there. It may have been purged due to space, it may not even have been saved in the first place (check you Cache-Control headers), it may not have been accessed.
You need to go in the Page Rules section of the Dashboard, add a new rule that covers your domain https://*domain.tld/*, https://*.domain.tld/*or similar depending on what you want to cover.
After adding a rule, select cache and select Cache Everything.
Exactly like a did, the * is a wildcard, so it covers all subdomains or pages that match it. If you read the pages I linked there are all the info you need explained really well.