I guess you have not done the required work to keep your position on google. Maybe other websites have worked on SEO...try maybe updating your site if you have not put any fresh news recently.
That not a new thing to happen especialy new site you may go back further than you are now, just keep updating it it will then fall in a good spot.
Well, your page or site could have been new which gives you a temporary advantage. Then, there's always the fact that your competition worked harder for that long tail keyword then you did.
Well if ur site keeps on ranking 1st page again 3rd u r for sure in google dance/google yo-yo effect and most of webmasters including me is under this effect from last few months and still no solution found for my site.
I can say that nowadays a lot of people know that you need backlinks to be on the top in google. Even my boss knows about the backlinks - and he is selling metal doors haha. I-net don't hide any secrets like before.
Its Google dance nothing else. Keep updated your site with fresh and original content. You will come back.
I have had the same thing happen and I notice everyone is saying to keep updating the site and such. Does this mean I need to update the specific page that I'm trying to increase the rank for is just my site in general needs to have fresh content?
Your site is in sandbox or a lot of competitors better than your site coming in with the same targetted keyword