E-mail Spam

I had a contact page up on my website, but I think that a bot or something started mining my e-mail address from the contact page. I’ve been getting lots of Mail Delivery System messages that have been returned to me. I was also getting lots of e-mails being sent to my webpage e-mail address. I had to delete that e-mail since it was getting hit so hard. Any ideas as to how I can stop this problem?