It's a clear case of maya not being mental just obsessed with anuj n being stubborn.
I suspected it too, that there will be a reveal that it was a trick to guilt trip Anuj, but makers wanted to seriously show that she is sick by giving her the headaches and visions of MaAn taunting her.
It's super sad that so many social issues are taken up so that Anupamaa can give a bhaashan on them and are then just slipped under the rug.