Severe nausea 4 weeks post op

I am 4 weeks post op from a para esophageal hernia repair and Nissen. So far the recovery has been slow, but steady. Over the last week I've had 4 episodes of something feeling like it is caught in my throat and I have dry heaves. After the 4th occurrence, I have developed severe nausea that will not go away. Had to start taking Zofran.
Has anyone had this experience? What could be causing the nausea and is this the new " normal"?
Appreciate any guidance.
Thanks