Heidi Montag was left in tears after her video received negative reviews

Heidi Montag's debut single "Higher" reached No. 7 on the iTunes Top 10 pop chart, despite being panned by her biggest critics - her fans.

"Looks like all the haters are also buying it!" Montag tells American magazine Us Weekly in its latest issue.

The negative comments - such as "the crappiest video I have ever seen" - left Heidi in tears, and even gave her sleepless nights. "I just started sobbing uncontrollably," she revealed.

"I cried myself to sleep that first night after my video came out.

"I just couldn't understand why people I didn't even know felt the need to be so cruel and hurtful toward me."

"I am just a 21-year-old from a small town in Colorado trying to follow her dreams," Montag says.

The Hill star's beau, Spencer Pratt - who directed the wannabe popstar's new video, was there for support. "I just held her and told her it was going to be OK," he said. "This is just part of being an artist. If it were easy, everyone would be a pop star."

"We were at the beach and, literally, Spencer had his camera and a boom box in the trunk," Montag recalls of how the video concept came to be. "We did it in one take, maybe two, and it took us 20 minutes to film and cost us zero dollars.

"We had other ideas but we couldn't afford them," Montag says.