A source says the ball is in Kylie Jenner's court

By Melody Chiu and Michele Corriston
Updated November 23, 2015 04:15 PM
Credit: Holly Heads LLC/Splash News Online

That was fast!

Just a day after news of their split broke, Kylie Jenner and Tyga held hands in a Snapchat asking fans to “chill” – and hit up the American Music Awards looking as in love as ever.

“They’re very much back on,” a source tells PEOPLE.

Jenner (in a white House of CB dress), 18, and Tyga, 26, proved as much by packing on the PDA at Justin Bieber‘s AMA afterparty Sunday in Los Angeles.

“Kylie and Tyga were definitely affectionate, kissing and holding hands,” an onlooker tells PEOPLE. “They were nuzzling at their table and being super engaged with each other.”

But just because they look picture-perfect doesn’t mean all is well, a friend of Jenner’s cautions.

“Nothing is really set in stone. It’s kind of up in the air,” the friend continues. “Kylie keeps throwing everybody off, including all of their friends. In theory, they’re kind of done and not going to be together, but then she’ll go and post a Snapchat of them holding hands. Everybody’s super confused by it. There’s not really an answer one way or another, but without question, the ball is in her court. Things are definitely shaky.”

Those close to both celebrities aren’t all Team Kyga, either.

“He treats her really well, but they’re not necessarily a great couple together,” the Jenner pal says. “A lot of their friends love them separately, but it’s also one of those things where they might be great people as individuals, but they act differently when they’re together. They’re not as carefree.”

So what happened between the Keeping Up with the Kardashians star and “Rack City” rapper? The first source says Tyga had to spend his birthday alone after he seemed to betray Jenner’s trust.

“She took him back after he begged for her forgiveness,” the source explains. “He claimed that everything was misinterpreted and a huge misunderstanding.”

Neither Jenner nor Tyga have publicly commented on the breakup and makeup, though she posted a paparazzi photo of the couple holding hands to Instagram on Monday with the caption, “Chaos.”

The couple began dating last fall but became more open after Jenner turned 18 in August.

Still, Jenner has said she tries to keep their romance private and doesn’t like to “talk about every little detail of my relationship.”

“Everyone who knows me, knows I’ve always been a relationship girl,” she recently wrote on her website and app. “I’ve never believed in the idea of casual dating or being with two people at once. I feel like I only have room for one person in my heart and I want to give whoever I’m with all the attention they deserve.”