Hi, sorry you lost your little one.
I would go off the D&C date as the date for tracking how long before my next cycle (although I would go of the day you passed the baby as the loss date) KWIM? I know that post m/c your temps are all over the place as your body is trying to get back to normal and it may take a few attempts of getting close to O before it actually happens. After my 1st m/c I don't think I ovulated. With the next 2 m/c's I ovulated like a week later than normal. Definately follow your hcg drops because you'll want to make sure it gets below 5 just because it gets confusing when you can't take an hpt because you won't know if it is a false positive. HUGS