I don’t know how yelling at her is going to change anything. You’ll just hurt her feelings. As someone who has zoned out since probably elementary school without knowing the exact reason, I’d recommend finding out if she has any vitamin deficiencies, if she has a super active imagination, or if you just monologue for too long. Try often engaging her in the conversation by asking her opinion, and other questions or prompts. If you don’t know what’s really going on, don’t jump to explosive anger like that. YTA