If you fear your site may be infected by malware, there're several diagnostic on-line tools which may be useful:
https://quttera.com/
https://www.gravityscan.com/
https://www.siteguarding.com/en/sitecheck
https://app.webinspector.com/
https://www.metadefender.com/#!/submit-ip
https://transparencyreport.google.com/safe-browsing/search?url=mysite.com
https://safeweb.norton.com/
http://www.scamadviser.com/check-website
Do not use only one of them; does not exist a "magic wand" which reveals for sure if and how your site is infected .
Everyone of these tools is different, so everyone of them may be useful in a different way.
