K.L.
S.,
You have a right to be scared. This can be very dangerous to a pregnancy, both for you and your baby. I know its hard to not pick up your 2 year old, but it will be worse if the blood clot becomes worse. There are many different stages, and since they sent you home on bedrest, I can only assume that the clot is sealed and is "old" so it is at least stable. Very important... if you have any bleeding, notice a decrease in the babies movement, and sudden sharp pains, go to the hospital immediately. The most common cause of this, if you want to research it, look it up by the name "abruptio placenta", or placental abruption. Keep all your doctor's appointments, and do any testing they recommend. Be religious about it because its both of you that are at risk.
As for your mother being on Coumadin, it's not that type of clot. Somehow, the placenta has either separated partially or been damaged. This can seal and never be an issue, or become worse. It does put you at risk for other complications, but not clotting disorder similar to your mothers. If they suggest c-section, from personal experience, its not that bad when considering the option of laboring and having an emergency c-section when both of your live's are at risk. But there are many women that have had normal vaginal deliveries with this same condition. Good luck.