I'm glad you got them, but you need to sit down with her with some literature and have a heart to heart with this woman.
I'll play Devil's Advocate and give her the benefit of the doubt, and say she was unaware of the complications her actions would cause. Even then it strikes me as overtly cruel to take away someones Antidepressent medication as a form of punishment for a frivlous thing like drinking.
That's like taking away insulin from a diabetic because they had a regular soda.
You need to think this through it strikes me as extremely odd and unhealthy.
Good luck.
Oh, and hide your meds. If need be, you can get extras cheap online. Lexapro is very cheap overseas and it helps to have cache of medicine when needed. Perhaps a trusted friend can hold them?