sigh It happens. You can't change people but you can change how you're perceived. The first thing I want to say is that being "shy" isn't an introvert trait. Being an introvert is merely about how you recharge your batteries and build relationships. Being an introvert means that at the end of the day you like to retreat into solitude and recharge your batteries. That social situations drain you. That you prefer to build a few, close, intimate relationships rather than be everyone's friend.
So, the shy thing is something you're going to have to work on. You can't merely rely on the fact that you're an introvert and use that as an excuse to be shy. It's ok to be shy... but when you're selling yourself, you don't want to come off as shy. You're going to have to fake it. If you want to think about it like pretending that you're an extrovert, then so be it. But fake it.
I just got an awesome job. I beat out some other highly qualified people. People much more qualified than I. I did much of the same things you did. I looked up the people who were interviewing me. I figured out some points I could mention that would make me "connect" with the interviewers. I did great, I got a call back for a second round.
I was sure that if I impressed them once, it was a fluke. There was no way I was going to strike lightning twice. But alas, I struck lightning twice. I was honest. There is that old interview question that asks "what's your greatest weakness?" Well, here is your chance to explain your introversion and turn it into a positive.
I told them my natural inclination is introversion. I love working alone. I love reading a case or contract and ripping it apart into its component parts. However, I told them I was also very aware of how this could be a weakness, and that I go out of my way to work in teams if I see I'm isolating. I added that a personal mantra of mine is an old african proverb that says "If you want to go fast, go alone. If you want to go far, go together."
you see what I did there? I was upfront about my introversion. I didn't apologize for it, but I admitted how it can be a shortfall (likewise, extroversion can have its shortfalls. Like dammit, can't you work on your own? do I need to hold your hand?) I told them how I was working to make sure that though I'm an introvert, it won't be a liability. And I added some inspirational bullshit about teamwork. Recruiters love that shit. The hardest part is making bullshit sound sincere.
But seriously, the worst thing you can do is define your introversion as being "shy." Shyness is not introversion. Antisocial tendencies are not introversion. In fact, you can use your introversion in such a way as to make people think you're an extrovert. Because I'm an introvert I like to build strong individual relationships. I like to just sit with one person an get to know them. If I have to go to a networking event, rather than worry about meeting all 50 people in the room and exchanging cards, I decide to have maybe 3 good, deep conversations that night. I may only meet 3 people, but those 3 people all of a sudden think they've had a great experience and like they really know me. When they find my card in their wallet, they'll remember me.
But you know... go to five networking events, just connect with three people and all of a sudden that's 15 people you've made great connections with.
I can be very very shy. My natural inclination is to think that everyone else is better qualified or better liked than me. I can't help that. Maybe people are more qualified, I can only work on my qualifications. Maybe people are more liked? I can't figure out what's in people's heads. But I have to do all this stuff. So, I fake it. I pretend I'm an extrovert. I pretend I am the life of the party.
Anyway, best advice is be upfront about it. turn the "negative" and turn it into a "positive." and fake it till you make it.
now, if it was a job like salesman... then I would just say turn and run. Shit, I could never do that! I'm in law. So I just have to go over contracts and work with my fellow lawyers. Maybe spend sleepless nights going over cases and maybe present them to a judge and debate it with opposing counsel.