Ovulation after miscarriage

Verity

I miscarried on 17th Jan at 5w4d and if I count that as my cd1 it means I'm currently on cd12. I've started using OPK's for the first time now and there's barely a faint line. I'm pretty sure I should ovulate a week today- how dark should the line be a week before ovulation and how long did it take people to ovulate following a miscarriage? I'm determined not to miss our window for BD'ing!