That certainly sounds like malware. The question is, is it on your browser or on your server? Your site is currently returning a 503 error (service unavailable), so I’m unable to check if it’s server based. The fact I cannot reach your site suggests it is server based.
Have you tried your browser’s safe mode, or a different browser? Better yet, a different non-mobile machine? If you get the same behavior anywhere else, then it’s certainly server based. This means your site has likely been hacked. It’s OK, it happens, no need to panic. You should work through the suggestions in FAQ My Site was Hacked.
If it turns out to be your browser, uninstall it and reinstall from a fresh download.
I’m sure you know the following, but it’s worth repeating for all to see:
Never ever execute code from a pop-up. Never call a phone number from a pop-up. If you feel the need to call for help, find the right number from a reputable source.
