That's the thing, there's a ton going on here. Attachment, transference just to name a few. And they're strong. Mentally you've created an image of your teacher as being a source of happiness. You've overinflated her good qualities and frozen that image of her in your mind. Basically you aren't seeing the real her anymore.

A good therapist should be able to help you talk through these issues so you can see her in the correct light and move on.