I had continued heartburn after my DD was born. I needed to stay on protonix (an equivalent to nexium) for almost a year. First, you may need some time to let your stomach and esophagus heal. Also, there is literature that says suddenly stopping a PPI (the type of drug nexium is) can cause a rebound in acid production. It's best to wean off of these drugs. You can try lowering the dose gradually by switching to a smaller pill, and eventually starting to take it every other day, then every second day, etc. Another option is changing from a PPI to an H2 blocker (like Zantac or pepcid). They reduce acid to a lesser extent. Then wean off of the H2 blocker in the same way. If your symptoms flare up, just go back to the dose that controlled them and wean it even more slowly. Good luck! You should eventually be able to get off them, but it might take some time.
Lauren (2004). HG from week 6 to delivery. Zofran, reglan, phenergan, unisom and B6, protonix, prednisone, PICC, IV hydration, and TPN.
Angel baby (April, 2011)
Madeleine (2012). HG from week 5 to delivery. Zofran, phenergan, unisom, protonix, Zantac, PICC, TPN, and IV hydration.