It is better to only take the Yamini medicine. Yamini is a oral contraceptive
pill. If you take the unani liver
tonic along with Yamini, it may not act at all as Yamini will induce the liver enzymes and whatever tonic you take, it will be metabolized soon. Also, it is not recommended to mix two types of medicines.
You can consume as much water as 5 liters, it is not harmful.
Hope I have answered your query.