Simon Bainbridge is an Editorial Director of the British Journal of Photography. I just read the interview with him on Lens Culture: Finding Your Signature: Advice For Emerging Photographers
It's good to come across words like that when feeling tired and frustrated - it gives an energy to proceed:
"Learn from others instead of referencing them. Try and understand what makes something work instead of using it as a style guide. Think and analyze—and let that seep into your practice. Practice a lot. Follow your instincts and see ideas through to their conclusion.
Then do the opposite. Follow blind alleys. Go places you don’t want to be. Work hard, even when it’s not working, and eventually your ideas will lead to interesting photographs, and interesting photographs will lead you to ideas."
The second paragraph is particularly helpful - I need to try something new to find the missing bit which will connect current works, or perhaps come up with something completely different.