Flow Duplicate Value Error when trying to add a campaign member

Question

I have a flow where I want to add users with a specific profile to new campaigns as campaign members. Users with this profile all have contact records with the same email address as the email on their profile.

The flow is setup to

1. get the profile records

2) decision element to check if users email is the same as a contact email as that's what I'm using to link the two

3. Creating a loop
4. Doing a get record for the email in the loop
5. Decision to check if there's a contact id in the get contact id records
6. Assign Campaign members values
7. Add to collection
8. Create campaign member record

I'm getting the error, "This error occurred when the flow tried to create records: DUPLICATE_VALUE: Attempted to add an entity '0038I00000M9xFM' to a campaign '7018I0000001O5O' more than once."

Any ideas what I need to do so it's not trying to create a duplicate?