Protecting My Gmail Account From Spam & Spoofing.

I had received an email from one of my contacts (or so I thought) a few days ago in which I replied only to find out after talking to them, they hadn't sent no emails to me. It never occurred to me that it could be spoofed. Ive read several support articles on how spammers are able to spoof an email address,signs to look for,etc.,but I still do not have clarity on how to better protect my accounts. Does Sophos have a way I can manually scan an email or file? And if not, can sophos run scan on individual email address' and files? Any help and feedback would be so appreciated. Thank you and have a blessed day...