I drank it throughout my last pregnancy, and will do so again this time. Was having a hard time, as well, due to nausea, but that seems to have pretty much passed.
I don't know that I would actually drink more than a cup a day, though. I alternated between red raspberry leaf tea, and pregnancy tea, and will probably do the same again this time.
I really love the yogi nursing tea the best, but there was something in it I didn't really want to drink while I was pregnant. Anise maybe? Also, being in Canada, nobody sells it here, so I have to have someone ship it from the States for me.