Have you told your OB this? Not judging at all, 8 bags of tea just seems like a lot of herbs to take in everyday (even if there is no caffeine, some herbs have not been tested or proven safe in pregnancy in large quantities).
Having said that, I used to be a tea addict but stopped drinking it (and coffee) when I got pregnant. Once I was out of first tri I started to drink peppermint tea a few times a week. The reason I stopped is because there is conflicting research about green tea and other tea herbs (like hibiscus) in pregnancy and I just didn't want to chance it since there are not a lot of studies.
There is some evidence that consuming green tea around the same time as a prenatal vitamin is a bad idea because the compounds in green tea will interfere with folic acid absorption, but no studies have been done to show what damage (if any) there will be. I recall reading in WTEWYE and another book that green tea drinkers should space out their tea drinking and vitamin taking by a few hours to play it safe.
I have read this as well, I guess I am talking more about generally not knowing how herbs affect pregnancy. Kind of like a class-c drug, you'd take it only if the benefits outweighed the risks since researchers don't know what the risks are. I can't wait to get back to drinking teas regularly though---I had to give away over $100 worth of David's Tea to my SIL when I got pregnant.
There are actually very few herbs that are harmful during pregnancy. Even the harmful ones need to be taking in "medicinal doses" (whatever that means) in order to be harmful. This is a good list to go by: http://www.americanpregnancy.org/pregnancyhealth/herbaltea.html
The only ones I would avoid are the ones that say "potentially unsafe" on them, and I waited until second tri to have a cup of chamomile since it had insufficient info about it. Honestly, one cup is basically water with trace herb juice in them and not enough to get benefits OR harmful side effects from.
But yeah, I drink green tea in the evening and take my prenatal in the morning, just in case. I'm not overly paranoid, though. I also just ate a cold turkey lunch meat sandwich and enjoyed a feta/hummus/spinach wrap on Monday. I'm basically playing russian roulette with my baby.