I don't know, something weird is going on. I unplugged my ethernet cable and back in and my site is fast again, this happened yesterday I did the same thing and everything sped up.
It remained slow on my phone, so I turned wifi off and then back on on iPhone settings, now it has has sped up on my phone. I'm sure this time tomorrow it will be sluggish again, pretty sure this only started to happen since I changed to Cloudflare. If its happening to me on multiple devices it must be the same for everyone else