All of this is wrong.

1) doctors’ notes don’t do anything. You either call in and use sick time and it’s excused, or you call in and don’t use sick time and it’s unexcused

2) you don’t have to give any info and they shouldn’t be asking for details

3) since Target combined all types of PTO into one generic “sick time” bucket, you can call in for any reason and don’t need to justify it. Just know that if you don’t have sick time or if there’s a pattern (i.e. calling in for every weekend shift for a month straight) you’ll get a performance conversation about it. Otherwise you shouldn’t be pressed.

(I can get why your ETL HR wanted more info, in case an LOA or workplace accommodation would be needed, but they can cross that bridge if and when they come to it)