My website was on page 18 on google for a keyword that has a high competition but a large search volume ( more than 6000 exact local search per month ). A few days ago my website achieved page 5 for the same keyword. I checked also the position of other interesting keywords and I noticed that they ranked in higher pages than before. this situation lasted for like 4 days and today when i checked the position of the first keyword I found that it got back to the page 18 as it was before.
Any explanation for this?