My partner deals has suffered from depression/anxiety for years. He’s on a medication given to him by a family doctor (snri) and has been for a couple of years now.

Every day he wakes up in a different mood, which I am very used to and generally know how to support him &amp; handle it. As of lately, I have noticed something new. His stare changing. It’s almost like he is emotionless. He woke up this morning in a pretty bad mood. Distant. Just all around mean and over life.
But his stare is almost like he’s not there. Pupils dilated. Looks directly at me like he sees right through me. It’s just different. Something is not right.
I’m concerned.

I am no stranger to mental illness. I have borderline personality disorder and I grew up with a father who had terrible mental health issues. I remember seeing him have a similar stare and it scares the living hell out of me.

Any insight? 
Thank you