Alex Trebek to Undergo More Chemotherapy After Setback During Cancer Treatment

"Jeopardy!" host Alex Trebek gave an unfortunate update on his health, and described why he will soon begin another round of chemotherapy.

In an interview on "GMA," Trebek sat down with ABC News' T.J. Holmes and revealed that he lost a bunch of weight after finishing up his first round of treatment for stage 4 pancreatic cancer.

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“I was doing so well. And my numbers went down to the equivalent of a normal human being who does not have pancreatic cancer, Trebek explained.

He said, "we were all very optimistic," and the doctors stopped his chemotherapy and switched him to immunotherapy.

After the switch, Trebek said, "I lost about 12 pounds in a week. And my numbers went sky high, much higher than they were when I was first diagnosed. So, the doctors have decided that I have to undergo chemo again and that's what I'm doing."

As we reported, it was only days ago that Trebek gave fans an excited update as the 36th season of the legendary quiz show kicked off, announcing that he had finished his chemotherapy and was "on the mend."

Now, Trebek describes his symptoms as bouts of “excruciating pain” and “fatigue.”

He also says the experiences has left him battling with depression and "sadness."

Even though he is fighting for his life, Trebek does not want people to feel sad for him, and explained that he has lived a long and successful life.