I've got kinda the same problem.
My Apache keeps being yellow and I can't stop it - If I try I get this error:
15:27:15 [Apache] Attempting to stop Apache (PID: 8060)
15:27:15 [Apache] Problem killing PID 8060
15:27:15 [Apache] Check that you have the proper privileges
I am opening XAMPP as administrator so it's not that.
As you said, I may have double clicked the stop button but now I can't seem to kill it.
What should I do? I can't find apache in the task manager