There are ways and means of doing this - especially for those who send out junk mail.
There is actually little point in blocking the various senders emails as they rarely use the same ones twice - if you find that a certain type of email always comes from @sendjunk.pl or something you can block that ISP rather than the whole email address
Have just received an email that looks as if it has come from me? I suppose all I can do is put my email address in Block Sender, but have just checked my email link from my website and if I do that any email sent from there will automatically go there too! Hmmmmm!! What a pain!
Check your virus protection is up to date -you could have a virus lurking in your address book -or it could have come from someone who has your address in their address book and they have the virus