The character you seem to have is only your pride. Unless it's exerted it's of no value. Which means you have to get into situations where your pretence gets stripped for your character to show. Only then someone will attach significance to your character.
Probably you give too much attention to what meets your eye. One simple exercise is acting as if you are blind or closing your eyes while talking.
Practice asserting by writing. You may not be able to react at a given moment. But later you can write about how you really wanted to react. This will give you some self confidence.
I know what you mean. I spent a goodly portion of my life crippled by my shyness. The only thing that ultimately helped was that I gave up caring what other people thought of me. You have to accept your own value as a person before you can move beyond your limits.
For me, overcoming shyness was a very slow process and it never entirely went away. But working with the same people in the same environment for significant time, I slowly became more confident. Best wishes, it's not easy.
Something I do pretty often is actually start out with some variation of "I'm not a great conversationalist, but I'm trying to get better, so, there's going to be awkward spots". Or, "sorry, my brain often just freezes up in conversation. I have thought about the things we're talking about, but I can't pull them from the freeze at the moment and it's embarrassing". Or something like that. Maybe that could help. Dunno, it helps me anyhow.
@Flenflyys I find it hilarious that all the guys jumped in with "do this!" when I've learned, that is NOT HOW TO HELP A WOMAN. At least not right off the bat. Your advice is actually best comment among the comments made.
That is a panic attack from social anxiety. One of those things where it is possible that the more you force yourself to do it the more comfortable you will become. You could also take anti anxiety meds on an as needed basis to chill you out a bit.
That can be very challenging. I'm pretty shy in person myself. I do a lot better online. But online takes a little more trust and effort to build relationships with, so it's a mixed bag.