If you have a backup, restore from it…
One look at your site and it looks broken in several ways.
There’s a redirect forcing https, but then there’s mixed content being blocked over https (meaning some scripts won’t load… you cannot see the warnings on google chrome or firefox?)
My plugin doesn’t look like it has been updated, or if it is some options are not optimized.
Deselect all checkboxes and check “Disable Font Awesome optimization”.
If you scroll down on pingdom, most issues are related to the revolution slider… check your settings there, since those should be deferred if possible.
There are some files served from api.autopilothq.com too, not sure if they are needed.
You have 3 google fonts being included by revolution slider, those are not enqueued in the header so my plugin cannot optimized those.
You have google analytics and some facebook related buttons or content… this will bring score down.
Looking at the site, I see no way you could have had a pingdom score of of 98 before unless there were several changes going on, unless pingdom was having a problem.
Try to put back the plugin that you have removed and test again, because it makes no sense a drop from 98 to 75. Also test from different pingdom locations, because sometimes they show different results.
