Exploring Cancun (Cancún)

Hallo, I'm a german guy from Berlin who planned a trip to Cancun with a friend but got ditched. So now I'm on my own. I've heard that Cancun in September is a little bit quiet so I'm asking myself if I should still go. I was very looking for to see Cancun and it's beautiful area, but I think it might be also very depressing to be there all by myself. I would be happy to get some inside information and some tips from locals so I could decide whether I should come or not.
Hope to hear from some of you.

Steven