How do I stop doubting myself?

help pls

I learned how in a strange way. Maybe my perspective will help.

I also used to doubt myself A LOT until something happened to me recently.
I was supposed to go out with a girl (me and that girl have many mutual friends). Apparently, when I asked her out she thought I meant in a platonic way, and she didn't have the courage to correct herself. I was sure for half a month I'm going on a date with her, but she and ALL of our mutual friends knew she didn't mean to date me.
I saw ALL the signs right away, yet instead of breaking it off I asked our mutual friends. Instead of telling me the truth, they reinforced the illusion she is interested in me. I kept asking and asking and they kept reinforcing until one day they abruptly told me to drop it and break it off. "Why?" ->"She isn't interested in you". "No shit. Since when?" -> "She just isn't.". And then the truth came out. She wasn't interested since the beginning and all of the anxiety and annoyance I felt throughout the half month of waiting were really meaningless.
I was right straight off the fucking bat.
There was no reason for me to doubt my instincts and ask other people. I was fucking right all along.

Listen to yourself more. Even if you're wrong, trust yourself. You are important. "To whom?", to yourself. Put yourself above all. You are always right, even if you aren't.

I dont know, I just knew that I was great.