I really feel for you. WLan can really suck on the battery; yet your experience is not normal.
Your first stop for advice should be the batteryguide.
Maybe you got some app running, that is draining the battery? The regula Facebook app is renown for all kinds of bad effects. Or maybe your phone is infested by a malware, that is mining crypto currency in the background?
The guide should really help you, unless you got a broken battery of course.
Well, that should be visible, as the ones you read are listed in a light grey script in the “latest threads” list, while the unread/new ones are in black.