According to my naturopath, you can take wormwood capsules while nursing. It's usually a no no, but you have to weigh the benefits. Just make sure you take them with black walnut hulls and cloves, these will kill the eggs. There is a supplement called "Juglans Artemisia" that contains all three and you could find it at the health food store.http://www.viablehealth.com/featured/prod05.html
I've taken it while nursing and it did give dd a little runs, but she seemed otherwise fine.
Good luck! I think there are homeopathic remedies out there too, but I have never tried them.