"At the end of the day, when you die and when I die, it doesn't matter how much money is in our bank account," Kourtney said on Sunday's season premiere of Keeping Up with the Kardashians

This season of Keeping Up with Kardashians started off with a bang.

On Sunday’s brand new episode, tensions between Kourtney Kardashian and her sisters Kim and Khloé took center stage.

“Khloé and I, the last six months, have not been as close,” admitted Kourtney, 39. “I just feel like I’m constantly being criticized and picked on. In the past I used to just brush things off, but I just don’t want to tolerate it anymore.”

Khloé, at the time pregnant with daughter True, took issue with her sister’s “attitude” problem. “It confuses me how Kourtney is confused that we’re butting heads,” she said. “Trust me — if I wasn’t pregnant, I probably would have drowned you in the f—ing pool.”

But Kourtney’s tension with Khloé, 33, was nothing compared to what was about to go down with Kim, 37. The drama kicked off when Kim suggested they plan a family photo shoot and agreed to take on the massive challenge of coordinating everyone’s schedules.

“It’s really important to me that our family does a Christmas card this year,” she explained. “It’s been a tradition for so long. It’s one day out of lives for the year, and we have these memories forever. It’s just something fun that we can all do together.”

But when scheduling issues arose, Kourtney refused to budge — prompting a knock-down, drag-out fight between her and Kim.

“No one wants you in the f—ing shoot. Get the f— out of here and go,” snapped Kim. “I need Kourtney to not be so f—ing annoying with a stick up her a— like she f—ing runs this s—, because she doesn’t. She’s the least exciting to look at.

Kourtney stormed off, but the argument continued over the phone.

“I’m not here to be mistreated by my f—ing bitch family,” she said on speakerphone, sobbing. “Kim saying that I’m the least interesting to look at — who even speaks like that? You don’t say things like that. You guys just have really different values than me. I choose to be a mother to my three kids. I’m not here looking for another job. I already work enough — more than I would like to. What’s natural to me is being a mother. And I don’t expect everyone to have the same interests.”

“You would honestly think that we have more jobs, so [you should] work around our schedule,” Kim fired back. “You do whatever the f— you want to do and you don’t do s—, so be accommodating to the people that actually do s—.”

“All everyone f—ing says is, ‘What’s your job?’ ” Kourtney said. “If I had enough money, I wouldn’t work. I wouldn’t do the show. I would be a full time mom. That’s what I want to do. The guilt I carry every day from not being at home when they get in from school, not doing homework — my kids suffer. Honestly, it’s like, we have a disgusting family. I’m ashamed to be a part of [it]. It’s just gross.”

Later, Kim acknowledged that she’d been rude, but refused to back down.

“That was rude, but I wanted to be rude. Because she’s so f—ing rude all the time. Everything revolves around her,” she fumed. “I’m not going to tolerate her f—ing rudeness. I’ll be 10 billion times ruder back to her, every single time. Until she just cries when she sees me. Everyone walks on f—ing eggshells around her. She’s f—ing rude. She’s so goddamn entitled. She’s such a mess. Gremlin. I’m not going to play around with her anymore.”

When Kourtney returned to talk things over a few hours later, she was still upset.

“I’m not going to spend my time, whether it’s my sister or not, with anybody that talks to me that way or thinks that way about me. Everybody has different priorities,” she said. “At the end of the day, when you die and when I die, it doesn’t matter how much money is in our bank account. What matters to me is my memories. I don’t give a f—.”

“I’m not going to be around people that bring me down on a daily basis,” she continued, crying. “I’m just doing my best.”

Khloé, in an attempt to mediate, suggested that the sisters all “stop judging each other” and pointed to her own recent move to Cleveland.

“I will move to another state at some point, or another country,” Kourtney interjected. “I cannot wait for that day and hopefully just won’t have to have these fake relationships.”

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Eventually, Kim rearranged her meetings to accommodate Kourtney’s schedule and the photo shoot came to fruition — even though the tension between the sisters was clearly lingering. In fact, it even stopped Kourtney from showing up to Kim’s baby shower a few days later.

“I really hoped Kourtney was going to get over herself and just show up, but she didn’t,” said Kim. “So I don’t think she’s big on family. Because if she was, she’d be at my shower.”

But there was one person who appeared to be in a surprisingly good place with Kourtney: her ex Scott Disick, 34, who reluctantly opened up about his relationship with Sofia Richie, 19.

“Honestly, everything’s been going pretty well lately. This is the first time I’ve ever been with anybody other than Kourtney, so it’s definitely different, but it’s been a really good thing for me,” he said. “It’s a little bit different for me to talk about what’s going on now. Sometimes I feel guilty that I’ve moved on.”

“One part of me is really happy that I’m able to care about somebody again, but there always is some feeling in the back of me that feels guilty because I’m moving on from Kourtney,” he added.

Nevertheless, Disick said he was doing “amazing, for like, the first time in my life.”

“I think that Kourtney and I have been through a lot. It’s an ongoing struggle, but I think she’s doing well now and I’m happy for her,” he added. “I feel that I’m able to now live my life the way I should.”

Keeping Up with the Kardashians airs Sundays (9 p.m. ET) on E!