Reply/to address for replies to emails that received no reply Steps: 


I send an email. 
I wait some days, and I receive no response (the recipient never replies). I now wish to send a follow-up email. 
I locate the first email I sent (either by searching or scrolling, in either my "sent" folder or "all mail", doesn't matter, 
same outcome). 
I click the reply button or hit cmdr (doesn't matter, same outcome).
I compose a second message.
I click send. 


Expectation: 


My second email should go to my recipient. 


Unexpected outcome: 


My second email is sent to myself instead. 


I'm new to Apple macOS Mail app. I'm more familiar with Gmail, but I recently switched to free my email from my web browser. However, I don't understand why anyone would want this behavior, and I'm hoping there's a way to fix it that I've not found. 

UPDATE: 

In troubleshooting after the comments below, it seems this problem occurs only for ignored emails sent before I switched from Gmail web app to Apple Mail app. I guess that's good news (in that eventually the problem should become irrelevant the longer I use Mail app), but why should this even occur? 

Software: 


Mail app version 12.4
macOS version 10.14.4 (Mojave)
You should check the recipient/ To email address if that mention your name then it will come on to your email address.