I think what is happening, is that you are growing. I do not mean by age, but by personality. What you need to do is to look things from a different perspective. You say that you used to have creative ideas and more energy, perhaps that is not what you need at the moment. Comparing your current time to the past will always be wrong. You should try to find happiness in wherever you are.
You can find a new hobby or do more things as suggested above, but I feel that what you need is to find happiness in yourself. I believe that the happiness you used to find in doing different things and hobbies, is around you somewhere. Try to find that feeling of satisfaction in yourself.Things you can do,
1. Write a diary. And if you are more high-tech and all, then you may consider a blog, or perhaps write a diary on Word or something.
2. Meditate. Nothing religious (or if you are religious then you may do that is you want to). But here I mean that you should find a calm place and just stop thinking. Take a long break. Life is not always full of energetic events. What you need is to see that.
3. perhaps I am wrong, and maybe you are just tired of doing the same things over and over again. Then you should pause, and write down five different places you want to travel. And then, travel.Good luck!