Sorry to ask, but I'll make it heaps quick. The other day I was checking google to see if my SEO work had any affect on my rankings. Well one of my keywords hit 130 or so, I thought great. I checked the following day and it fell to something like 441. Now zilch... its not in the SERPS anymore. The site is still indexed, and is first for www.mydomainname.com and www.[mydomainname].com, and appears first when using site:. The domain is almost 3 months old. (10 weeks). Perhaps my link building was a little quick. I'm not positive about that though as I had kept it quite low. < 100 page links (Not domain links) a day. Perhaps in Google eyes its too quick. If that is the case, what can I do to regain my SERPS? Continue link building? Cheers.
Without knowing what your domain is, it is hard to guess, but it sound like you are in the Google Sandbox. And you will just have to wait it out. And 100 links a month is to fast. Even at 50 you are pushing it.