Am I going insane

Been riding 2 months on a cb650f and felt very confident in the corners and riding (new to riding so confident to my ability)

Had a puncture last week and had a new metzeler z8 tyre put on the rear by a local motorcycle garage (fitted and wheel balanced) and "scrubbed" it in and now on around 110 miles on the tyre however I feel a slip in the rear that I never felt or noticed before the puncture.

It's making me lose confidence in the corners and leaning the bike.