The only scene I remember clearly: the main character drowns their phone in the kitchen sink seemingly on autopilot and shortly after has no memory of what happened and doesn’t even realize they’ve forgotten anything.

This may or may not be recurring. I think they may have also smashed their phone on the ground and flushed it down a toilet before. A friend/partner/family member may have been trying to contact them during the times their phone was dead and have been worried about it.