Anyone else getting spammed so much?

I am getting massive amounts of spam. I would walk away from the site for a few minutes and receive ten or more spam comments. All of the spam points to domains that were obviously created for spam or phishing purposes. I thought of banning IP, but it looks like the person(s) is using proxies, as each message comes from different IP.
Not sure what to do. But I think the overload is responsible for the strain that my server’s cpu is suffering from.
Anyone else getting bombarded? Any suggestions?