Cycle start date!?!

Hello, 

I have been ttc for three years and two years ago I went to GP, who then referred me to gynaecologist, myself and my parter have had all tests and we are both healthy. We have had to loose weight (me 1.5 stone in 2 months and my partner 3.5 stone in 2 months) this has been very hard, but if we didn't we would not get considered for IVF. So we have been referred yay!! and in the meantime trying clomid. 

So finally my question that I could really use any advice that's out there. It is a bit graphic but something that I'm struggling to get an answer from my male registrar. I'm not meaning to be sexist far from it, but I just don't think he gets it. So my periods have gone really stop/start. I have PCOS so they have never been regular. But lately they start by me only knowing when I wipe myself underneath, no discharge in my underwear. This goes on for a few days then nothing. Then 1-2 days where there is light flow, but discharge in a sanitary towel. Then nothing. Clomid should be taken days 2-6, when do we think my day 1 is?  really want to get this right. Thanks 😊