Waking up groggy and fatigued

Hi all,

I've been a night owl all my life but have recently (past month-ish?) changed my routine to going to sleep at 10 and waking up at 6 am. My sleep is pretty deep (according to my watch) but I have pretty intense and pretty prolonged sleep inertia. I am groggy and extremely exhausted and I'm not sure what it is because I wake up without an alarm and due to the sunlight.

I wanted to ask the FB family if anyone else has/had a similar problem and if they did anything to fix it.

P.s. i used to suffer from insomnia but that hasn't happened in a while.

P.p.s I have PCOS so I'm on a low carb (not keto) diet.

Edited