Everything has changed for Leah Messer, Kailyn Lowry, Chelsea Houska and Jenelle Evans since last fall's season finale of their hit MTV reality series "Teen Mom 2." The network released the official trailer for the upcoming seventh season of the show, providing a first look at all the drama, tears, and fights which starts up where the last season left off.

Chelsea Houska

At the end of season six, Houska and her boyfriend of one year Cole DeBoer took their relationship to the next level when he moved in with her and her 6-year-old daughter Aubree, whom she shares with her ex-boyfriend Adam Lind. Shortly after DeBoer moved in, he asked Houska to marry him. "We're getting married," Houska tells her new fiancé while lying on the couch in the clip. "I know," DeBoer says with a laugh, and little Aubree reacts with an enthusiastic cheer.

Kailyn Lowry

Lowry and her husband Javi Marroquin experienced ups and downs in their marriage last season, and they were able to work on their marriage and build a stronger relationship. But Lowry reveals another test which was placed on the couple when she opens up about a recent miscarriage, and the couple tearfully discusses their loss in the promo. "You know how much I wanted that baby," Marroquin tells his wife, choking up. But the United States Air Force member drops another bombshell that could test their newly stable relationship. "I am deploying," Marroquin tells his wife, and her jaw drops from shock. Cameras were present and captured his tearful goodbye. "I can't believe I'm not gonna see you," he tells his wife as she wipes tears from his eyes.

Leah Messer

After the divorce from her second husband Jeremy Calvert, Leah Messer sought treatment at a rehabilitation facility to learn how to cope with depression and anxiety. Her coping skills are put to the test when she gets involved in a contested custody battle with her first ex-husband Corey Simms over their twin daughters Ali and Aleeah. "Corey is trying to take our kids from me," the mom of three says in the promo. "What's life without your kids?" The clip cuts to Simms' lawyer announcing that he was awarded primary legal custody of the twins.

Jenelle Evans

Shortly after her breakup with her allegedly abusive ex-fiancé Nathan Griffith last season, Jenelle jumped right into another serious relationship with a man named David Eason - much to her mother Barbara's disappointment. "Do you think that mommy gets a lot of boyfriends really fast?" Barbara asks Jenelle's oldest son Jace in the promo, and he replies, "Yeah." The clip cuts to a scene where Jenelle is sitting at a restaurant with Griffith, and he expresses his concern over Eason, who was allegedly just released from jail on a domestic violence charge. "I'll snap his f-cking neck," Eason says in the clip. But Griffith isn't the only one who doesn't approve of the new man in Jenelle's life. Her mother Barbara gets into an argument with Eason, and he closes a door in her face. "You are the worst boyfriend she's ever had," Barbara yells while Jenelle cries.

Watch the full official trailer below, and be sure to tune into the season seven premiere of "Teen Mom 2," set to premiere on Monday, March 21 at 10 p.m. EST on MTV.