Are experiencing a cold shift in your career? People aren't returning your emails for lunch or happy hour meetings? In the office some co-workers don't seem to have time to chit chat with you anymore? Even the light hearted banter you felt within your work team isn't quite what it was. Don't worry about it; as you shift so does your working relationships with people.
As you begin to shift into focus and intention about your career through words and actions, those around will shift as well. To some it will be a wake up call to get themselves in gear. To others, who never thought much about your skills and abilities, they now view you as a threat against their own career goals. Some, well they just don't have the time anymore because the economy is shifting and they may be adjusting their lives to accommodate that.
Don't take the coldness you feel to mean that you should change your behavior back to how you used to be or take a step back from your forward movement in your career. Instead, take it all as a clear sign you are moving as you should be. You're actions are being noticed and the plans you have for your career are within view.
If you don't believe me, pull your mentor to the side and ask them if they see anything negative in your actions or behavior in the last month or so. I'm betting the answer will be "keep up the good work".