Several Commentators have struck on some pillars of the issue. Whether it is lack of time spent thinking or lack of time spent encountering new ideas. I will suggest two more possibilities: 1. If you are working now, then perhaps a large portion of your creativity has been spent on the problems you are currently facing. Having done this for an entire workday is it any wonder that when you finally have a free moment, you are tired? That all you hear in your head is mental static?
2. Consider along a similar vein, creativity may be like a muscle. Certainly, I cannot think on hard problems for more than 8 hours straight. Suppose then, that with the transition into the pattern of work, you muscle has become tired. Naturally, it will produce little when un-rested. In my opinion, rest can come from breaking patterns, or from 'stretching' by encountering new ideas, trying to think of or solve puzzles in new ways.
I hit this wall very quickly after college. And I was frustrated for about a quarter, before I found ways to break the mold. What I found was Ted Talks, and news sources like Hacker News. Both these allowed my to be exposed to new ideas. But moreover, I got caught up in the excitement and the mentality of the communities therein. Instead of asking, 'could I ever do this?' I found my self asking, 'How could I not?'. This change in thinking is very powerful, in my opinion. It frames every one of your actions, and changes the tenor of your thoughts for the better.
The last thing I found that helped me, was starting a blog. I had been frustrated by the lack of career movement (shocker I know, and perhaps a bit naive at the time), and by the lack of fresh ideas and challenges. I found that by writing about my thoughts and about my projects, I achieved two things.
First, I found a new challenge, as I am not the best writer. Naturally, writing a blog on any kind of a consistent basis would necessarily exercise that part of me. And Second, I opened my thinking to items beyond just programming. I found issues and ideas flowing from things as simple as an ill-organized meeting.
I don't know if these ideas will help, but you should know you are not alone. Further, I encourage you to not give up, but more importantly, to be unafraid to look in novel places. To summarize a passage written by C.S. Lewis:
"The Man to loves the thought of flying may be discouraged by the loss of the first blush enjoyment when he joins the air force. But if he sets his teeth and continues to walk towards the goal of his original passion, he may yet find other interests along the road. Once he has mastered flying, though it's passion no longer burns as brightly, he may discover a love of gardening or of photography. So long as he is willing to surrender that first hot, bright passion for the quieter longer-burning kind. "
I do not recall the work, but it may have been The Abolition of Man... or perhaps the Great Divorce. If someone know better, I would welcome the correction.
In either case, It captures well the core of the issue. Lament not the loss of your first fruit, and look to the horizon for yet more harvest. Good luck sir/madam, We all wish you the best.
-Edit-
My goodness I am long winded. I formally apologize, but retain my hope that it serves well.
Also spelling and grammar fixes.