context: The film opens with a funeral for a young woman; the deceased is Dawn Wiener, the protagonist from Solondz's Welcome to the Dollhouse, who went to college, gained a lot of weight, became pregnant, and committed suicide. Her brother Mark (Matthew Faber, reprising his role) reads the eulogy while Dawn's tearful parents (Angela Pietropinto and Bill Buell) sit in the audience.
  A few years later, Aviva, Dawn's cousin, desires to have a child. She has sex with Judah (Robert Agri), a family friend, and becomes pregnant. Aviva's parents are horrified and demand she gets an abortion. While the abortion is technically successful, it is implied via a fractured, emotional conversation with the doctor (Stephen Singer) that Aviva can no longer have children. Not fully conscious, Aviva is unaware of this, and her parents, already fragile, lead her to believe all is well when she awakens, afraid to upset Aviva.
  Aviva runs away from home. She befriends a trucker (Stephen Adly Guirgis) and has sex with him; however, the trucker abandons her at a motel. She is eventually found by the Sunshine Family, a Christian fundamentalist foster home that cares for orphans and runaways. She tells them her name is Henrietta â the name she picked for the baby she was persuaded to abort. While at the Sunshine Family home, she discovers a dark side to the foster father; he assassinates abortion providers. His next target is the doctor who performed Aviva's abortion. The hitman whom the foster father uses is the same trucker Aviva previously befriended and had sex with.
  Convinced she is in love with the truck driver, Aviva flees the Sunshine Family to join him on his assignment. The murder does not go as planned as, in addition to the doctor himself, the trucker (whose name is revealed to be Bob) ends up accidentally shooting the doctor's young daughter when she steps in front of the first shot. The police find Bob and Aviva both in a motel room, and Bob commits suicide by cop.
  The film then skips ahead to Aviva back home with her parents, planning her next birthday party. During the party, she talks to her cousin, Mark, who has recently been accused of molesting his sister Missy's baby, although he denies having done it. The film skips ahead to Aviva's meeting Judah, who now calls himself Otto, and they have sex again. Once again, Aviva believes she is pregnant and is happy about it.
question: Why did Dawn commit suicide?
answer: Gained a lot of weight and became pregnant