Page is unresponsive while editting?

Hello and thank you for your time. I’m sorry but I don’t know where to find what version I’m in (I’m not the smartest when it comes to this type of stuff). I was simply adding some media to a page on my website, and when I clicked update it got stuck trying to refresh. A little dialog box appeared saying the page was unresponsive, and asked if i wanted to wait, or kill the page. I clicked wait, and waited, but the same dialog box appeared. I did this a couple of times then decided to kill the page since I couldn’t get out of the loop.

Now every time I click on the page to edit, the same thing happens, and I just close the page. When I view the page outside edit mode, it appears my changes actually did save, and I am able to see the page as it should look. However, if I click on edit, same thing happens as described above

The website is:
The page is (GROUPON):

Thank you for any help on this. My groupon goes live in a few days, and I still have much to do so I’m ready.

Jason