@anna12352 as I checked my theme version was around 4.4 current is 4.12.
Hence I did an update and it's working fine now.
However please note post UPDATE, you need to do the changes to your code from scratch like app installation, manual code changes, etc.
Also, the mystery is still not resolved why it got slowed.
Hope yours gets resolved soon.
It's PageFly - Shopify Page Builder App here and there's some notice I have when checking your site speed. Here's the results of your page speed checked on PageSpeed Insights: https://developers.google.com/speed/pagespeed/insights/?url=https%3A%2F%2Fwww.vanivrtti.com%2F&tab=desktop The score on Desktop is 78, which is not bad actually, but on Mobile, it only scores 29 so here's some of my suggestions to improve your site.
1. Remove all unnecessary CSS code, this might come from your theme code. You can contact Theme Provider to see if there's anything they can do to minimize the theme code.
2. You can try Lazy Loading as well to reduce loading time all at once. PageFly do offer this feature as default when building page.
3. Delete any unused third party apps. These are the 3 main sources that take up most of your store that eventually will affect the page speed.
So I hope that these are somewhat helpful for you in improving your site speed. you can also check out this article on Page Speed optimization . If you find this comment helpful, please give it a like and mark as solution. Wish you all the best!