I think at times what inspires us seems to fade away. I think its because our mind finds it hard to stay on a 'high' for prolonged periods. Some might say we have to experience the downs to appreciate the ups. I dont know about that but it could be that while you are feeling the absence of inspiration is a time of rebuilding your beliefs, a time of renewal, when the connection you previously felt is undergoing a transformation. Hopefully the feelings you mentioned (Ive had similar experiences with dusk and dawn times) will return with renewed excitement. Perhaps you are undergoing a period where youve become familiar with the old 'vibe' and sub-consciously you are creating a new one. I hope so.

If your interest doesnt return and you feel flat for an uncomfortable period of time there may be other causes for it that you need to look at.