Is your web site under attack?

Of course it is. Most web sites are under attack by many different forms of spiders and bots. You should maintain a good relationship with your provider. Check all your monitor specs either directly or question support to discover if there are any weaknesses. Forms are a favorite target to spam through. Make sure you have a Captura button or some kind of human interaction required.
If you are using a WordPress site, make sure you have one good security plug-in like WP All in One set up and running correctly. ALWAYS update your plugins to the latest versions. Some are for security and some are for better performance.
Always remove email addresses and their mailbox if you have not used them in a while. This is a favorite way for spammers to send tons of spam out and then your good email address will be black listed if it is the same domain name.
Some people will use FTP permissions to make changes. When dormant for too long be sure to remove or make the password very difficult.
These are all the basic things you need to monitor regularly to protect your site, business and reputation as well as your fellow internet users.