Lightroom 5 update, HELP!!!

I purchased Lightroom 5 four years ago, and it has been fantastic. In the last month it started crashing if I would let it sit for about 10mins without any activity, and it would not read a raw file on my new camera, so I figured it needed an update. I hit the update button in Lightroom, it took me to an Adobe page and from there I found the update, or what I thought was correct the update. Once I installed the update it prompted me to enter my serial number, then it said serial number is invalid. I called Adobe, (Yes, I know they no longer support Lightroom 5)  they sent a link for an update to Lightroom 5, which was a dead end. I searched and searched Adobe forums and found a new link for the full download of Lightroom 5 with the update,  so I uninstalled my current Lightroom 5 and reinstalled the new one, only the new download never asked for the serial number, and says it cannot open because there is no "Adobe Application Manager", so I downloaded the new copy of Adobe Application Manager, and the window is still popping up. However I can open Lightroom but it's now saying in Adobe Creative Cloud on my Mac, that I am in a trial of Lightroom, but when I open Lightroom it doesn't show any spot that says how many days are left in the trial. So did the actual download of Lightroom 5 with the update work without having to enter the serial number?  I am starting to become very frustrated, as I have clients waiting on their wedding photos, and all I want is the update my original Lightroom 5 said it needed. Please help!!!