Like to know if anyone else is using my Apple ID

Marking your own post as Solved may prevent others from trying to help because they think you have fixed your problem.

Did you change your password as suggested? Check your device list to see if there is a device signed in that you don't recognize. You can remove the device using the steps in the article below.

Apple ID device list -Check to see where you‘re signed in.    

 Apple ID Password Change.      

 What to do after you change your Apple ID or password - Apple Support     I suggest doing this before you change your Apple ID or password.

Change your password.