Colon/Intestine Issues (Urge to go and Thin Stool)

Hi,

I've actually went to my doctor today already and asked. However, I still have some weird feeling about this. Not that I don't trust him because he's one of the best doctors.

For the past 2-3 months, I realized that I would get thin stool once or twice in a month. When I google it, everything comes down to colon cancer and I was really scared. The reason was because I got all the symptoms that was listed on websites.
My symptoms are thin stool, urge to poop even when I just did 5 minutes ago, gas pain, diarrhea, bowel movement changes from time to time, and fatigue.

I went to my doctor and told him about everything that I get. He told me that on the internet, there's a myth going on about thin stool is a tumor or something blocking inside your colon. He also told me that this is not true. He said with everything I said, I have a sensitive intestine and that's why I would get diarrhea after when I eat. He explained everything to be and I think what he said could also be right. He just told me to watch what I eat and only to be concern if the stool is dark, constipation, or contains blood. However, above all that, it's true that I can normal stool most of the time. Also, I realized this happens usually around the time of period. He also said that I'm only 24 so at my age, he's not that concerned.

He didn't send me to do any tests and told me I shouldn't be concerned. I'm still worried after talking to him. He's a really good doctor and he concerns a lot for this patients but I don't know why, I really need this proof that I'm fine. But since he's not telling me to do the tests makes it not necessary for me to do a colonoscopy. Do anyone here agree with this?