Dustin Diamond Wonders if He Got Cancer from Cheap Hotels - TMZ

Dustin Diamond's cancer diagnosis has been hard for him to deal with emotionally ...

Dustin's struggling to come to terms with having the type of lung cancer he has -- stage 4 small cell carcinoma -- because it's normally caused by smoking, and he's never been a smoker.

So, we're told Dustin can't help but wonder if his cancer is the result of his frequent work travel over the past 20 years.