Hello Mike,
mdl5299 wrote:
I have 1 VM with two interfaces. They both are on the same vswitch, but one is a different Ip address. However when I shut down this VM, the network loop issue did not go away.
You do not have any "bridging" or similar configured inside this VM?
I did not look in the networking performance - shame on me. I was in a hurry to get the services back up and running. Is there away to go back in time?
That is quite natural to prioritize getting the systems up. 
Do you running stand alone ESXi hosts? If they are managed by a vCenter Server then you will have performance data collected automatically and available later.
How many nics are going from your ESXi host to this switch?
In which way did you notice that there was a loop or high network traffic? Was it only from the external Nagios not getting ping packets through or from other detection?