I wonder if maybe you could get a cotinine test and just see what your levels of nicotine are and how they compare to a sort of average for cigarette smokers. Most tests on vapers so far seem to indicate that we are getting levels of nicotine somewhat lower than smokers. This varies a lot depending on experience, equipment, vaping style etc... The issue with pregnancy is that while nicotine does not seem to be particularly harmful at low levels in adults, it can (probably, possibly, sometimes?) be harmful to a developing fetus. While there is no question that you are getting less of the other harmful stuff (tar, carbon monoxide, etc...) with vaping, it's really impossible to say how much nicotine you are getting. If you could get a cotinine test that would give you an idea of where your nicotine levels are compared to a smoker or NRT user and might help you and your doctors make a more informed decision. If you are going to continue vaping you should probably try to drop your nicotine levels as much as you can.
I don't know. This is a really hard question. It's easy for us to say, "just stop", but as former smokers I'm sure many of us realize that's much easier said than done. You have my best wishes for a safe and healthy pregnancy!