no, not at all... Virus killers will check your email and alert you when you have a virus but will not delete your emails.
The firewall stops certain things being accessible over t'internet.
Could it be that there have been internet problems with the email provider or that these emails have been sent to the junk/trash can?
try emailing your family and ask them to respond to a number of email addresses if you have them to see if it will help in identifying where the problem is.