It was simply the huge traffic inflow and our server had only one core, poor thing ahah. We've upgraded it to only two cores and it's day to night difference. Server side of course has some weight but it has caching so it is quite fast.

Major problem for now is that in some places it still doesn't retrieve data with the right projection, for example when creating a menu it loads all the pages with everything in it. That's why I'm switching to Relay to make this easy pie and more reliable