Is anyone nursing while pregnant?

I had been nursing my toddler on demand who will be 3 in Sept up until my milk dried up around 14/15 weeks. She was still dry nursing to go to sleep at night but was Soooo close to being weaned. About a week ago she was going to sleep, nursing and she sat up and smacked her lips a few times like she was tasting something and she yelled MILKIES! I checked and yup, I've started lactating again. Now she wants the boob constantly :/ Everytime she starts nursing I start contracting very badly. I guess I'm wondering if anyone else is nursing and its giving them contractions? I'm telling her no and trying to only do it at night for a few minutes but she's flipping out and sadly its easier to give in but I obviously don't want to have this send me into early labor!!!! I had my 1st baby at 35 weeks so I'm nervous.