question about clomid

So back in November my obgyn told me to try metformin for 3 months and if no success then we will try clomid. I called last week to discuss starting clomid and they haven't called back. I called again yesterday and still no response. I plan on calling again in the morning and raising a little bit of hell. They are usually so good about calling me back! Anyways, come tomorrow I'm on cycle day 5. Is it too late to start a clomid cycle if I can get her to call it into the pharmacy tomorrow? Not sure how early in my cycle im supposed to start it. Thanks!