Help! My Gallery site was suspended by hostgator

I had my gallery site at www.adoroportugal.com and a few days ago I got a message from my host (hostgator.com), saying:

"I was forced to suspend the script /home/heasousa/public_html/index.php as it was causing a high load on the server, and due to it affecting all of the other accounts on the system, I was forced to take immediate action for the health of the server.

Unfortunately I do not have any specific recommendations for this script, however, in general, adding some sort of caching mechanism, where the script does not need to generate a new page with every request, helps to lower the over load that a script will cause. Likely the original author or support group of the software that you are using will be able to help you to understand how to add something of this nature. "

Has this ever happened to anyone? How can I solve this situation? I have no technical knowledge.

Thanks
Helena