It is natural for websites to rise and fall in the search engine rankings. In fact, when new sites are discovered by the search engines and receive their initial rankings it is quite common to see them rise high into the search engine rankings.
Google particularly is good at this. With its emphasis on fresh search results, new pages get an unnatural boost in search engine rankings. After a couple of weeks you’ll see your website fall in rankings and settle in at its natural position in the SERPs.
Another time when you’ll see sharp rises and falls in your search engine rankings is when the search engines make adjustments to their algorithms. These adjustments occur every day. Several times a day, in fact. But occasionally they disrupt the SERPs to a degree that causes many web pages to rise and fall in the rankings and many website owners get alarmed over this. Don’t.
Again, this is a natural response to major changes to the search engine ranking algorithms. After a while, you’ll see your site bounce back to its natural place in the search rankings again. It could be positioned a little higher than before or a little lower, but the algorithm update will cause a major flux.
Search engine rankings naturally fluctuate from day to day. This is natural. If you see big swings one way or the other, wait it out. You’ll see your sites likely settle in at their natural search positions.