Does Buddhism kill creativity? My decrease in creativity does most likely not have anything to do with my feeble meditation attempts, because it is natural to have ups and downs, even when it comes to creativity.

But still, meditation deals with ridding oneself of attachments by observing mind states objectively and I think that following through an idea and turning it into a finished piece of work requires quite a lot of attachment and devotion to the project. 

I suppose my real question is: is it possible to balance being a practicing Buddhist and a creative artist?
Many working artists are also Buddhists. A number of high profile creative people such as Leonard Cohen, Herbie Hancock and Steve Jobs are Buddhists. See Wikipedia's long list of celebrity Buddhists, many of whom work in creative industries.

Most people report that creativity increased after taking up meditation. At least one scientific study reported that meditation enhances creativity. The Huffington Post has reported much the same news. 

Buddhist practice requires not just moment to moment awareness, but also considerable continuity of purpose. If one emphasises only the former then one is unlikely to make much progress. It's a bit like walking downstairs and forgetting why you went down there. 

So there seems to be no reason to think that being a practising Buddhist would "kill creativity". And no reason to think you cannot balance being a practising Buddhist and a creative artist. I personally know at least a dozen people who do just this.