A weird behaviour of home page

Hello, there is a very weird situation with my home page. Everything was fine till few days ago. Any page, even without a content, once I make it a home page loading 7-10 second, according to GTmatrix, but if that page, not a home page the loading time 1.4-2 seconds. I have no idea what can cause that problem. Hope you can help. I've also granted a support access.
Thank you.