Hi Atul.
What you said, "While revieing the questions, I realised that I knew the answers on the first instinct but with over analysis I picked the wrong ones," indicates that you need to tighten up your approach to answering questions. After all, if you have a solid approach to answering GMAT questions, you won't be answering them by "instinct." Rather, you will have solid reasons for choosing one choice over the others that won't be swayed by "over analysis."
So, it appears that you need to keep practicing with individual practice questions, and possibly also continue to learn concepts and strategies to strengthen weaker areas. Then, once you're achieving high accuracy in practice sets, you can go back to taking practice tests.
For some insights into how to prepare effectively, see these posts.
How to Score 705+ on the GMATHow to Prepare for GMAT Verbal