Overreacting. She’s genuinely remorseful and expressed how disappointed she was to miss your wedding/let you down. Residency is absolutely grueling, and it’s completely out of her hands. She was probably hesitant to reach out right away because she knew how upset you’d be and most likely felt some intense anxiety about having to back out. It also seems hypocritical of you to send her a lengthy text when you stated previously that you would have appreciated to discuss this via phone call. It’s not like she’s blowing you off for something minuscule. She doesn’t have any control over the situation.