I need someone to fix my Google Analytics tracking for my website.

I have a website and have been using Google Analytics for years to track visits to the site. A few weeks ago, however, I noticed there was NO traffic showing up. I did a test myself and also had a friend sign into my site. Google Analytics is not tracking visits. I'm not sure how to correct this on my own so need assistance. It's probably something very simple, but I don't have the expertise to fix it myself.