Why Did Jessica Break Down Onstage?

Jessica must be having a tough few weeks!

First, she fights "fat" comments when pix of her at a concert in Florida caused an uproar, and last night, she apparently had fits of crying and confessed that she wanted to run off the stage while opening for Rascal Flatts in Grand Rapids!

One concert-goer called into a Grand Rapids radio station to describe the scene:

"So I’m watching Jessica Simpson and after her third song, she would kinda just stop singing.

She would look right at the camera and say, 'Sorry I can’t do it.' No one could figure out why because she sounded great.

After that almost every single song that she sang she would just start crying. And she would mouth in the microphone 'Please God help me through this.'

At one point she said all she wanted to do was to walk off the stage.

She made it sound like she was upset because she couldn’t sing as well as she thought.

Then she got really emotional during a song about spousal abuse that she had written. That was the song when she started seeming to have her breakdown was the song about a woman having the courage to leave her abusive husband or whoever."

Was Jess taking the song personal? Is there more to her relationship with Tony (or Nick?) than meets the eye?

Not so, says her reps, who claim Jess was just not feeling well and felt horrible about disappointing her fans.

Radar has more from concert eyewitnesses HERE.

Photo courtesy Getty Images