When to start using progesterone cream if no ovulation?

by Phoebe
(New Zealand)

We are trying to conceive baby number 2, I have PCOS and a very long cycle of around 40 days. I am pretty sure that I am not ovulating during my cycle, my cervix is not changing and I'm getting no 'egg white' discharge or pain, which I did get when I conceived my son (we had been TTC for about a year and I was using lots of natural remedies and acupuncture which I am doing again this time).

When I do get my period its very heavy with clotting and bloating before hand. So I would like to know if I should start using the cream around 2 weeks before my next period is due (slightly hard to tell as cycle is often a few days less or more), or on day 14 to promote a shorter cycle. I have just received the progesterone and I am on day 11 now. My Doctor has prescribed Chlomid for the next cycle so how and when/should I use it then as well - if I got pregnant without knowing and stopped using it after 2 weeks when my period was due could this make my levels drop and cause miscarriage?

Sorry for all the questions! I have looked at your website extensively which I think is great but still wanted some help with this if possible. Kind regards.