Hello,
We have checked your site and see different results
good http://prntscr.com/j3wfs7 with good server response time http://prntscr.com/j3wh8r
and bad http://prntscr.com/j3whwb few mins later.
So, contact your server provider to find out why you have such difference from time to time.
We can do nothing with this, unfortunately.
Regards