I've definitely been there! I've always been a bit shy myself so it's something I had to work through in order to be more confident in interviews. At first, I didn't perform well, but it's something you get better at with practice.

If you find yourself giving into anxiety in the middle of an interview, it's OK to take a moment to center yourself before you start talking. A lot of the questions you're asked in an interview are meant to make you think, so most interviewers understand that you might need a few seconds to come up with a good response (especially to tough questions.) It also helps if you've gone through some of the questions that tripped you up before and practiced your responses before your next interview, bonus points if you recruit a family member or friend to play the interviewer. This way, you'll already have some sense of what to say already and that will eliminate some stress. If you find yourself utterly stumped, it's ok to say, "Wow that's a really tough question! Let me think." to buy yourself some time. It also lets the interviewer know that you're taking the question seriously instead of just blanking out.

It can feel like you're constantly on the spot in an interview, especially if you are shy or anxious, which is why I like to think about it like this: If this company called me in for the interview, they must have the sense that I'm qualified for this position. This meeting is to figure out if they'd like to work with me day-to-day, so it's best for both of us if I'm as honest as I can be while still putting my best foot forward. If they don't like that version of me, then it's probably best that they find someone else for this position.

That kind of mindset takes a lot of pressure off of you and makes it more of a test of whether you and the company are a good fit for each other. If not, it's probably not due to some big failing of yours, it just didn't work out!

Keep applying and learning as you go. Nobody's perfect, so you will make some mistakes, but it's all part of the process. Best of luck in your next interviews!

No worries, everyone gets nervous, some of us more than others. I had a less than fantastic interview yesterday but they still want a second interview with me. I think what I'm trying to say is, you're probably not coming off as badly as you think you are. We are our own worst critics. :)