Facebook have rolled out a new update today, the change means that your contact email displayed for your profile will have been replaced with an address for you @facebook.com

Your original email contact address is there but hidden from your timeline, to reinstate your original address, go to your about page and edit your contact information. Click the pull down arrow next to the email addresses to hide or display your preferred email address.

If anyone does contact you via your new Facebook email address, the email will appear in your private message section on your profile.