[alanaut]

Judging from this comment, I would say you lack confidence. Recruiters and interviewers can see this coming from a mile away. Perhaps, you are trying to jump up the proverbial software engineering ladder to fast...

I would highly recommend you read the book: Decode and Conquer. I would also recommend Cracking the Coding Interview and Cracking the PM Interview. If you can solve those problems on a white board, you can pass a technical SE interview.

I would also suggest you:

1. Work on a problem for a few minutes and try to solve it. If you can't, look at the solution and understand how the solution was derived. Go back and solve the problem again. You are not finished here. Go back a few days later and work on the same problem - repeating this several times a week. Over time, you will grow more confident and can quickly recall concepts that are potentially causing you to perform poorly on your technical interviews.

GL