CLOMID and cycle length??

Hi girls,
Okay, so I was confused about my cycle length since the doctor told me that clomid had a 31 day cycle and I got my period on day 23-24 (spotting started late on day 23). My appointment with him wasn't until yesterday, which I was thinking was day 28, but I guess I should have counted it as day 5...
I called the nurse today and she said yes I technically should have started two days before I saw the doctor but agreed it would have been impossible to get in to see him before then to get the prescription...
SO she said I could either start it now or wait until the next period and go from day 3. I'm not convinced I will get a period without clomid (last month was the first time in over a year and only lasted less than 3 days as it was).
SO has anyone here ever taken it later than they were supposed to?? If so, did it change anything?? Did it mess things up? Was anybody successful?