Pages loading too slowly

For about the last 30 days, I have seen a dramatic increase in the load time for each page.  Where it used to take less than 3 seconds to load each page, it now takes 10 to 15 seconds per page.  This means a simple task like creating an invoice takes around 5 minutes because of the number of pages and length of time each page loads.  I am using Internet Explorer 10 as my browser but have even attempted to utilize Google Chrome.  Both browsers produce similar results in terms of how long each page takes to load.