K.P.
D.,
I am editing my original comment below because I just read the update from you. I also had the same situation that you're experiencing to happen to me as well, with the blighted ovum. And as you have concluded, it is simply just one of those things that is beyond us. So, I am thankful that you are accepting it to move on so that God can bless you and your family with another healthy pregnancy.
Kim
Original Comment: My prayers to you and your family. My strong suggestion would be to have the hormones checked asap. Often the spotting is due to low progesterone levels. The doctor could give you some progesterone, if so. You can also use natural progesterone cream. If it turns out that your progesterone levels are low, the I would suggest having this level checked in between pregnancies on a monthly basis at the time of the month when it should be its highest. If you see that it's too low (google or ask dr. about what's normal range for certain times of month), then you can use progesterone cream yourself on an ongoing basis to get it normalized before you are pregnant. I did this and now have 4 children. Some doctors will say they'll wait until you're pregnant to check your progesterone level and see if it's normal. And a select few might be proactive and check your levels before pregnancy. I would suggest doing it before pregnancy in the future.
Wishing you the best,
Kim