Hi,
I'm no expert on this but from what I've read, it can be problematic conceiving if you have a short luteal phase. A short LP is considered anything less than 10 days.
So sorry to hear that you've suffered a m/c. However, it's encouraging for you that you have been able to conceive.
A short LP is usually down to progesterone deficiency, which can be treated. It may be worth visiting your GP if you haven't already.
Good luck.