Google ranking always falls and fluctuates when you are new and even later because of the sheer volume of competition.

Yes, this has happened to me as well, but the key is keep focused, keep posting content and as your site gains steady viewership and increases in website age it will level off and begin to stay pretty level

Rankings on google will always fluctuate especially when your site is fairly new, it will even out in time

This is just normal. After sometime it will stabilize and less volatile. It will would be going up and down still but not too much numbers compared when it was just posted.

Yes I also experience this.....competition!

you Google rankings will constantly change because of keywords and others are trying to get their keywords to out rank yours so you will always be in competition .all the best Max

This is normal because every person is doing the same and you have to work hard to keep your level -

What I've noticed over the short time my website has been indexed is....
My site has grown in placement. I checked site:mywebsite and I had 5 pages of rankings. Something like 45 different google locations for 13 posts. So google has been adding ads on my site based on different keywords in my posts. So.....although a keyword may estimate 10 views a month, if google splinters the post into different locales, you can get more than the 10 estimated viewers. Make sense?

Yes, this is a phenomenon known as the "Google Dance." It's sort of an adjustment period until your rankings "settle in." This can happen for every article you publish. Nothing to really worry about.

Are you sharing all your posts to Google plus? If not then your ranking tank easier. If you don't have a Google Plus account open one today and also sign up for the analylitics. All my posts shared on Google plus get higher rankings. I think ranking can fall when newer posts come out. That's why you should always post as much as possible but quality credible content of at least 1000 to 1200 words.