Trial reconvened Monday as Ed Sheeran spent his fifth day in court, where he is being sued for alleged copyright infringement over his 2014 single "Thinking Out Loud" and expressed his frustrations.

Launched by Structured Asset Sales — who purchased a third of the shares of the song from the family of Ed Townsend, who co-wrote "Let's Get It On" with Marvin Gaye, in 2018 — the suit alleges that Sheeran's hit took elements directly from the song.

During the hearing, Sheeran, 32, took the stand and was questioned by his lawyer Ilene Farkas. At one point, he was asked what he would do if the court finds "Thinking Out Loud" to be too similar to "Let's Get It On."

"If that happens, I'm done, I'm stopping," Sheeran said.

"I find it to be really insulting," he added. "I work really hard to be where I'm at."

A rep for Sheeran did not immediately respond to PEOPLE's request for clarification.

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Later in the hearing, the "Lego House" singer was questioned by the plaintiff's lawyer Robert Frank. After offering up some stern responses, Sheeran complained about his line of questioning.

"You're trying to diminish my success," he said. "'Thinking Out Loud' was my first Grammy."

Amy Wage, Sheeran's co-writer for "Thinking Out Loud" also took the stand and explained to jurors that the song's tune sounded more like Van Morrison's "Have I Told You Lately," as it has the same chords in a different key. She also reflected on how she felt about being accused of copying "Let's Get It On."

"It was pretty devastating and pretty frightening because it's something we did not do," said Wage.

Sheeran also grew frustrated with the plaintiffs' musicologist Alexander Stewart, who previously argued that the songs were similar.

"I think what he's doing is criminal here," he said. "I don't know why he's allowed to be an expert."

Before the trial began, Sheeran hugged and exchanged a few words with Kathryn Griffin Townsend, who collapsed outside the courtroom last Wednesday.

On Thursday, Sheeran walked the court through his development as a songwriter by sharing that he has grown from writing one to two songs a day as a teenager to now writing eight to nine songs daily.

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"If a song takes longer than a day, it's not worth pursuing," Sheeran said.

The "Shape of You" singer said the creation of "Thinking Out Loud," was a "very collaborative" process between him and co-writer Wedge. Sheeran recalled being inspired to create the song after hearing Wedge "mumbling" the chords as he got ready to go to dinner and said he knew they needed to write a song to them.

The lyrics were inspired by their personal struggles as Sheeran's grandmother had been diagnosed with cancer, his "grandad" had died, and Wedge was going through a family illness, he said.

As the day came to a close, he gave further insight into the songs' development by sharing that the original chorus lyrics were "I'm singing out now" before being changed to "I'm thinking out loud," and sang both versions, along with performing the opening chords on his guitar.