Bad religion
Sharon was depressed and lacking goal and vision in her life. She was unstable and ended up getting involved in a sect espousing insane apocalyptic visions and teachings. This, coupled with her emotional instability and distress led her to commit a terrible act.
In the end, all the insanity taught by her religion turned out to be true, and furthermore, she could be forgiven, but she would have to love the God of the faith that she felt had led her down the wrong path, the God who had allowed such sorrow to occur. This she was unable to do, so she remained in her own personal dark hell forever.
It's surreal, at least in the end, but I don't think it's so difficult to understand. It can probably be interpreted literally or figuratively.