Mother Opinion affecting my veiw on life

I feel abit gaslighted or slightly anxious and feel the need to check if it's true what my mum said.
I told my mum that her friend's daughter who I'm friends with since kindergarten, told me that her son Avi who is 12 months is having a operation next week Monday. That her mum's partner is having a operation on Wednesday. We knew that the mum's partner was going to have operation.
But I had no idea my friend's son is going to have a operation next week Monday.

Anyway I told my mum since I was concerned. I thought maybe her friend told her too but she hasnt.

Then my mum said some thing odd about what my friend said to me. She said "She probably playing games with you"

At frist I felt a bit shocked my mum thought that. Also where did my mum got that idea from?
Then I started panicked and thought what if my mum is right. What if she is playing games with me. I've been lied too and be taken advantage and be taken as a fool!
I told my partner he said that what my mum said is based on an assumption and there is no evidence in her assumption. Which is true.

But I feel very pull , back and forth by mum's opinion and then what I truly believe.

I was thinking why would my mum say that?
My mum does have a very black and white thinking about people. She would tell me or my sister how this one person at work is bad and always label people as narcissistic. If its work people at work or a family member. They are always labeled ad narciastic. That they talk behind people back.

I'm just wondering how can I developed to think for myself and not be gaslighted or question what I believe that is influenced by my mum.

I will show the actually txt message my friend sent me down below. Just to give more content about the situation.

What my friend said
"I've missed our hangouts maybe next week we can catch up? Andrew has his op on Monday and Mike is going in for his op on Wednesday. Crazy times"

Your friend told you he is having surgery... why ask your mother to confirm what you friend texted you ?

I didnt asked my mum to confirm it for me.
I told her because she is friend's with my friend's mother.

It's just a feeling I get from reading what you wrote here @TeaFruit, that your mom, perhaps absentmindedly, didn't fully hear or comprehend what you were telling her, and, so, just said the first thing that came into her mind - not realizing how it would impact or effect you.

I think, at the end of the day, yes, listen to what your moms views and opinions are but have your own opinion/view as well. It might be the same as your mothers or might be different - it doesn't matter much as long as the love is there.

Is this the same friends you have issues with? I don’t know any person who would claim that their young child has a surgery to just play a game?

It's extremely frustrating and horribly depressing when people that you are close to, specifically family, don't always believe you. If I could figure out how to hit the agree button/emoji here, I'd agree with mote.of.soul though.