[ Pregnancy ] Open Question : Dr says to stop breastfeeding 16 month old since I'm 12 weeks pregnant?

She told me to do whatever I had to, but to stop because it releases oxytocin which can cause preterm labor later on and it's too demanding on my body. Lilly is so attatched to it though. If I try to refuse it, she gets so upset and is relentless about getting it no matter what. Going to sippy only isn't an option as she refuses it a lot of the time (except meals) and will only fall asleep with anything/one else if she is super tired and daddy gives her a bottle of milk or she gets so tired she becomes uncoordinated she hurts herself and daddy rocks her to sleep. He works nights though, so he can only do that 10 days a month tops, plus we travel every other weekend 400 miles away and I nurse her to sleep in her carseat (we go at night). So I'm kind of at a loss as to what to do. I know she doesn't **need** it and it's just a comfort thing but I don't know how to comfort her without it because she doesn't have a lovey, wont accept me rocking her to sleep etc. we have a night time routine that we follow (roughly)... but I'm not sure. I know some moms continue breastfeeding thru pregnancy and then tandem b/f, but the Dr. of course doesn't agree with that. I am however switching to a midwife so I can have a water birth and I will be asking her about it. In the mean time, what do you think?