Charlotte went through this at around 10 -12 months...Was horrible - usually she adored baths. She would scream and scream and scream.
(We never put anything in her bath water, although she doesn't much like shampoo, still doesn't, but has no issue with soap/etc)

We worked through it by getting in with her where we could, having showers with her, and when she was really bad we would sponge bath her.
Lasted about the 2 months, but it did get better, the phase passed and she adored baths again, still does.

Hang in there!