I feel like someone is using my apple id

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. As a precaution, change your password.

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 AppleID password, and

Enable 2-Factor Authentication.

https://appleid.apple.com/

Review this article and take additional steps as appropriate:

https://support.apple.com/en-us/HT204145