Sorry to hear you've been let down. I'm afraid such stories are not uncommon; fortunately for you students are also known to let academics down so places do come up even in September and early October. However, chemistry is a very competitive area of research. If you don't want to take up your newfound opportunity to take a year off, then you could try broadening your search. Many areas of life science use a lot of chemistry and there are usually more life science PhDs available. Materials or chemical engineering may also be an interesting move. Only think about these changes in subject if you think they'll be of real interest to you.