Users are visiting your site both through the non-www and www versions.
You need to set up a 301 redirect to get the non-www domain redirected to the www version as they are treated as separate websites.
You also need to set the www version as your preferred domain.
Hope this helps.
Arnold Majlath, Google Analytics Top Contributor
Was my response helpful? If yes, please accept it as solution.
Circle Me On Google+ | Visit me @ Redfly Digital
"With regard to your inquiry, a redirect may be needed if you are moving your Website to a new location or if you have multiple domains directing to the same top level domain. This would require incorporating a 301 redirect into your Website code, therefore, access to your Website files via FTP (File Transfer Protocol) is needed.
Please be advised that the Website of PORTMOREVET.COM is hosted on an nsWebsite service. This service has no FTP capability. You will have to upgrade your site to one of our nsHosting packages in order to take advantage of this feature."
Is there any alternative to the 301 redirect?