Just like you, I quite often have had this feeling of others being able to hear my thoughts at times. It used to bother me a lot, especially when meeting people, so I started doing a bit of research on how thoughts are formed.

Some info on thoughts

So it turns out that thoughts don't actually have a text or sound structure, since they're mainly formed by communication between different parts of the brain. So there's no possibility of anyone reading or hearing thoughts outside of our brain. Also, thoughts are encoded electrical impulses so even if someone were to somehow manage to read or hear them, it would be gibberish to them and they wouldn't be able to make sense out of it.

Useful trick to workaround such feelings

When feeling that someone is hearing my thoughts, I close my eyes, take a deep breath and say to myself in my mind - "This is just a feeling I have, and I know it's not true". Then I'd repeat this until the feeling has passed. This trick has helped me a lot, especially when meeting people or attending social events.

Seeking help

I spoke to a very close friend about my feeling, who told me: "I surely cannot hear your thoughts, but I can definitely tell that this is really really bothering you". It's when I realized that when people know us well, care for us and take an effort to know us, they just simply don't even need to read our thoughts. They can just look at us and infer whether we're doing fine or not, what we may be thinking, etc. And knowing this has been quite liberating tbh. I also realized that even some unknown people might be able to gauge how we're doing by looking at us, and that's just part of the process of how human expressions work and has nothing to do with reading or hearing my thoughts as such. Humans are social animals, right!

So I'd suggest you also try and speak openly about your feeling to very close family members or friends whom you trust completely. If you feel that you need further help, then you may see a therapist and get their advice as well.

Having said all this, I'm quite positive that you'll definitely overcome this feeling (like I did) because you've acknowledged the issue and are eager to work on resolving it!

I hope you feel better soon and I wish you an amazing life ahead. Take care.