Your profile will periodically change based on many factors. Be active, and you should not have a problem. By this I mean contribute: If it means answering a questions once a day, or publishing a hub, leaving a comment etc. This shows that you are active. The votes you get also affect it as does many other factors.
Actually scratch that, here is an exact quote from the Hub Pages help section...Bare with me it's sorta long I hope this helps a bit :)
"HubScore takes into account many factors and will change over time as data about its performance continues to stream in. It will also fluctuate quite a bit, seemingly at random, and that is nothing to worry about. The most important HubScore components that you should be concerned with include:
Amount of traffic - including percentage from reputable sources other than HubPages
The reputation of the Hubber - your Hubber Score and contribution to the community
The response of readers to your hub - including comments, thumbs up, etc.
The uniqueness of content - copying content already available on the web will be penalized
We reserve the right to change the factors used to assess a Hub’s HubScore as we continue to determine those that measure a great Hub. The bottom line is if you write original, useful content, your HubScores will reflect the quality and work you've put into them."