'Teen Mom' Stars and Their Kids

A preview for next week's finale teased her arrest, after she allegedly attacked Andrew in July.

Amber Portwood worried about "sabotaging" her relationship with Andrew Glennon and opened up about getting "frustrated" with him before allegedly attacking him earlier this summer.

In Monday's new episode of "Teen Mom OG," the reality TV star said her mood swings and depression had been getting worse, before snapping at her baby daddy on a drive to her psychiatrist's office.

"Because I struggle with bipolar and borderline personality disorder, I sometimes have mood swings and that can be tough on my relationship," she said in a confessional at the top of the hour. "Andrew has always been supportive of me, but I want him to better understand what I go through on a daily basis."

Explaining to him that she had been "getting pretty depressed" recently, she talked to Andrew about how important it was to keep an open line of communication with her doctor. Glennon said the doc suggested they move, with Amber agreeing it would make her happier to live somewhere where it "wasn't snowing literally 10 months a year."

The only problem: she didn't want to be far from daughter Leah, who lives with father Gary Shirley.

Tensions between Amber and Andrew arose when they drove to the psychiatrist's office, as Portwood opened up more about her mental state. Speaking about the crippling anxiety and lack of sleep, she told hm "it's hard living a life like this."

When she added she just wished people would "think of me as being dainty," Glennon tried to make light of the conversation, which Amber was not having. "You just gotta be dainty then," he said with a smile.

"That's easy for you to say, you're not listening to a word I'm saying. Your jokes are not appreciated at this time," she snapped. "We're speaking right now and you're joking. You're not listening. You're the worst person to talk to about this, honestly. Sometimes I just need my baby to talk to me. It's like talking to a friggin' clown."

She spoke with her psychiatrist about blowing up at Andrew later in the episode, admitting she got fed up on the ride over.

"On the way here I was getting frustrated with him, making light jokes of certain things and I know that's just him trying to make me, make it light, but to me, I'm like, no!" she explained. "I think it's his way of trying to help me lighten up and be happier and I should be more grateful for that, but for some odd reason it bothered me today."

Adding that she's been "very irritable" lately, hasn't been sleeping or eating well and has felt "combative," Portwood added that "everything" has been annoying her "to the point of getting enraged."

Amber also said she was worried about sabotaging her relationship with Andrew, noting it "would be horrible" if that happened. "I just wish I didn't get triggered so f--king easily," she said, "it's like a ticking time bomb. I'm there man, I'm right there. It's not me."

That time bomb may have exploded, as a preview for next week's season finale showed Portwood's mugshot from her most recent arrest. According to TMZ, Amber was arrested for domestic battery on July 5 after Andrew contacted cops and claimed she hit him with a shoe while he was holding their child. She also allegedly wielded a machete during the incident.

MTV has been filming the fallout from the incident, even following Portwood to court with costars Catelynn Baltierra, Maci Bookout and Cheyenne Floyd.

"Teen Mom OG" airs Mondays on MTV.