“You can’t please everyone. As long as you’re happy, that’s all that matters,” Beer tells PEOPLE

Madison Beer has always been vocal about dealing with cyber bullies—something she’s experienced every day since she was 14.

“Just because people follow you on Instagram, they think they know you personally but they don’t,” the singer tells PEOPLE of dealing with haters online. “But it’s never gotten easier or less. It’s just something I’ve been able to navigate and convert into positive energy.”

Still, she says it will never stop her from being her authentic self.

“People say I’m too skinny, but if I gain a little weight they say I look chubby,” Beer explains. “You can’t please everyone. As long as you’re happy, that’s all that matters. I don’t give a s—. I don’t change myself for other people.”

As for sticking up for herself, Beer says she does it occasionally. “A lot of times, responding is just as immature,” she says. “So if I do respond, I have to do it with class and grace. Just show people that they don’t really know me. But if you want to crawl into a hole and cry and not talk to anyone, that’s OK too. I have felt that so many times. At the end of the day if you feel like you’re a good person and your intentions are good, then that’s all that matters.”

The singer, 18, who just released the video for her single “Dead,” is currently working on new material, which she says will be ready this fall.

“It’s going to have an R&B pop vibe,” she says, noting that she’s a huge fan of Rihanna‘s sound. “I’m still in the studio now, but Rihanna is definitely an inspiration.”