There is nothing to panic about.
Service Host: Secondary Logon is a service that runs to allow Run as different user to work.
Secondary Logon
The Secondary Logon (seclogon) service enables processes to be started under alternate credentials. This allows a user to create processes in the context of different security principals. A common use of this service is by administrators who may log on as restricted users but must have administrative privileges to run a specific application. They can use a secondary logon to temporarily run such applications. If the service is disabled, this type of logon access is unavailable and calls to the CreateProcessWithLogonW API fail.
This service starts when a program or application is started by using the Run as different user option in the extended context menu (which can be opened by holding down the shift key when you right-click an item).
From Windows security encyclopedia
Multiple sessions of svchost are always present on modern Windows. I have 14 running on my system.
The Service Host (svchost.exe) is a shared-service process that serves as a shell for loading services from DLL files.
You, therefore, see multiple such svchost.exe running at the same time. This grouping of services also assists in better control and debugging should the need arise. Services run in svchost are implemented as dynamically linked libraries or dll files.
From Windows Club
Regardless, you should have a decent virus scanner and/or malware detector running on your system.