Well done to get to 13 months and still be breastfeeding, thats great!! I don't know what I would do if i were you, its such a difficult situation, but if you decide to discontinue breastfeeding, you shouldn't feel guilty because you got him to the first year.

Can you talk to a doctor about this, perhaps the doctor(s) who helped you concieve your son? I know breastfeeding is meant to stop ovulation, but it doesn't always. I've been breastfeeding exclusively for a little over three months and I got my period today. *Shrug*