Apple Mail not jiving with the server
I'm using Apple mail v11.2 on my mac mini (running High Sierra v10.13.3) to manage my gmail accounts. Whenever I read or delete emails in apple mail on the mac mini, it does not affect the emails on the gmail server. In other words, when I open mail on my iphone, all those email messages are either unread or not deleted. Often times, they will show back up on my mac mini! It sends/receives email just fine, but this gets frustrating- especially after deleting dozens of emails. By the way, the same does not occur with my iphone or ipad. Please help, b/c it's making me bananas.
Thanks!
Mac mini (Late 2014), macOS High Sierra (10.13.3)