How can I overcome defeating thoughts about myself and dating?

My friends repeatedly tell me a guy was checking me out or that men like me but I don’t see it, and I justify ever guy who checks me out as “oh he probably just does it to everyone.” I get hit on pretty regularly too but I’m too dumb to see it. I even had my best guy friend (I’d date him but he lives too far and now has a girlfriend) take me to two $300 dinners. My brother-in-law was like “yeah, he definitely liked you.” I always get skeptical when a guy smiles or stares at me, and I think it’s usually cuz I have something on my face or something.
I don’t feel sexy or like anyone is actually into me. Could it be the truth, or am I struggling with a self esteem problem that’s sabotaging me?
I want to think more positively and eventually get married.
How can I overcome defeating thoughts about myself and dating?
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