From StarryHeaven:

Megumi Yoshida (nicknamed: Useless Yoshi **Yoshi-dame**) entered university prep school after high school but it was difficult to make friends. Useless Yoshida wanted to make friends and because she knew her classmate likes presents, thought that was the best way to make friends. However, she doesn’t have much money, and when asked for some cosmetics, she shoplifts. Afterwards, useless Yoshida joined the shoplifting group and though she felt guilty in the beginning, she soon became accustomed to shoplifting without remorse. However after reflecting on the hurt she was causing to the people who knew about the shoplifting, she stops shoplifting and decides to make everything right again by paying back what she stole. But standing in her way are the members of the shoplifting group, Yumacchi and her friends.

From Tokyopop:

Confidential Confessions is a shocking new manga series that deals with many of the hard-hitting issues that teens face today. Using emotionally moving storylines and multi-dimensional characters, each groundbreaking volume tackles such topics as teen prostitution, rape, HIV, stalkers, suicide, and sexual harassment.

V.1 - Tobira (MOMOCHI Reiko)
1-3. The Door
4. Mistakes

V. 2 - Namida (MOMOCHI Reiko)
Tears

V.3 - Memai (MOMOCHI Reiko)
1. Our Future
2-3. Dizziness

V.4 - Itami
1. Pain
2. Distortion
3. Tomorrow
4. Forbidden Kiss

V.5 - Himitsu (MOMOCHI Reiko)


V. 6 - Uwasa

Series order as published by Konansha:
1: Itami (いたみ) (Pain)
2: Himitsu (ひみつ) (Secret)
3: Memai (めまい) (Vertigo)
4: Uwasa (うわさ) (Rumor)
5: Namida (なみだ) (Tears)
6: Tobira (とびら) (Door)

"I killed my sister. Now I will live as her."
Mischevious Nobara and good-girl Kotori are identical twin sisters. After their father's death, they lived with their grandmother and mother, respectively, but one day, while they had switched places, Kotori was murdered!

From Forbidden Garden

Midori moves from Tokyo to start her senior year of high school in Sendai. She saved her childhood friend Aa-chan from teasing, but the class boss, Erena, stirs up a revolt and makes her the new target. Midori can’t bear the never-ending torment and personally takes her own life. Midori gets a second chance at life, choices and revenge though. This is Momochi Reiko’s first challenge at a time warp story!!!