The reality star admits she's "scared to go," because it means leaving her three daughters

Teen Mom 2

star Leah Calvert is making the tough journey back to rehab in Thursday’s episode.

In an exclusive clip from the MTV reality series, Calvert confides in sister Victoria about how difficult it will be to leave her three girls for a second time to complete the month-long program.

“They’ll get through it. It’s going to hurt me more than it is them,” Leah tells Victoria. “I’m scared to go. I’m nervous to go.”

Last week’s episode saw Calvert leave rehab after worrying that ex-husband Corey Simms, father to her twins Ali and Aleeah, would gain custody of them by claiming she had abandoned them when she went to rehab.

“I know as a mom and the woman I am right now, that I need to go away to a treatment center for some help,” Calvert says. “I’m not trying to be a crybaby about it either. I’m just trying to go to get the help I need, and go on.”

Her alleged struggles with drug addiction have been an issue during her court battle with Simms for custody of the twins. She has previously spoken about being prescribed pain medication after giving birth to her daughter Adalynn in 2013, but says that she has stopped abusing the medication.

“I know I have to push myself through this, because when I get back, it will be worth it all,” Calvert says in the clip.

RELATED VIDEO: Teen Mom 2‘s Leah Calvert: I’m Not an Incompetent Mother

Teen Mom 2

airs Thursdays (10 p.m. ET) on MTV.