I found to this article when I asked the same question after beginning my meditation/mindfulness attempts 2 weeks ago.
I found a very convincing post (with more links inside) that explains that mindfulness is not as simple as just devoting all your brain activity to things that surround you, and if it chokes your creativity, you’re likely doing something wrong.
Another thing I’m wondering about, you’ve written you were feeling great. Perhaps the months you’ve spent in your meditation practice *did* ultimately sharpen your mind and senses since you’ve abandoned the practices?
To be continued as I read more, perhaps. Unless these responses are moderated.