I haven't seen a story about Trelawny's point of view on what happened that Halloween night so I thought I would do a short one shot on it.
Disclaimer-I don't any of the characters mentioned.
After Albus told her about the prophecy, she didn't know what to think at first but, once she realized what it meant for any babe born during that time meant, she began to drink in order to try and drown any thought of what she had possibly caused. Luckily for her Albus offered a place, and job, at Hogwarts though they both knew she wasn't a true seer and she vowed to do the best she could at her job.
She knew she didn't have the gift to see the future but she did have the gift to find those that did and taught them all she had learned from her mother. The day after the attack happened, instead of celebrating the defeat of Voldemort, she mourned the death of James and Lily and the the fact that their year old son was now an orphan.
She went to Albus and begged him to allow her to care for the child since she blamed herself that he lost his parents but, much to the distraught woman's sorrow, he told her that he was to go live with his mother's sister, brother-in-law and nephew. After that she delved deeper into the bottle when she wasn't needed to teach a class.
When she heard that the child was to, finally, come to Hogwarts she insisted that she wanted to make an apology to him for what her prophecy had caused and sought him out the first chance she got. "May I help you?" He asked her once he noticed her and tears welled to her eyes.
"I'm so sorry , if I hadn't made that prophecy then he-who-must-not-be-named hadn't gone after your parents and you." She sobbed before she turned and stumbled back to her tower, the tears flowing freely now.
Harry's friends looked at him, "What was that about?" The red haired boy questioned as he and a girl turned to watch the teacher leave. Harry shruged then suggested they get to class before they were late and the three of them soon forgot what happened.