If it is the site in your profile, I just checked it and it loaded fine. However, you may want to check your database. This happened to a client of mine and we discovered their database was hacked. A malicious script was inserted into a category.
Marshall CENLYT Productions - ms designs Affordable Web Design Custom Ecommerce Designs Responsive Websites Cenlyt.com
I looked at the site yesterday and again today and it didn't strike me as being slow. If it's a general problem check any third party content like site seals, images or stats and see if temporarily removing any of those makes a difference.