I wouldn't vape. We know that nicotine is bad, yes. Even if you're using the nicotine-free liquid, the long-term effects of the chemicals within have not been established. I like to err to the side of caution in those types of situations. As for seafood, stay away from he big four (shark, swordfish, king mackerel and tilefish) and keep it to 2-3 servings a week, just like when you were pregnant.
I mean I wouldn't eat it as regularly as you use to. Some fish is obviously good for you. Wic give breastfeeding women salmon so it must not be all that bad