Utilities Premium says that it is included in my subscription, however, when I go to use it, it says that I need to activate it

If you are referring to the 'free' bonus Norton Utilities Premium, NUP, that was included for having Automatic Renewal enabled for your 360 subscription, that is no longer being offered. 

You are able to keep using the free offer as long as your current subscription that gave the bonus is still valid. When you come to renewal of 360, the offer is no longer available, even if you did allow the automatic renewal.

Check in your Norton Account at   https://my.norton.com and click on the user icon at the top right and then click on Manage My Subscriptions. Look for NUP and see if it says the Annual Subscription says Active, Expired, or Disabled. If you see expired or disabled, the above information would seem to apply.

If it says active, copy the product key that is listed there. Then open NUP and click on the "?" for help, and click on About Norton Utilities. Then click on Change Product key and enter your key there. That should get you going again.