No advice, really, but I do have a comment. My mother took Lexapro and her doctor prescribed her Celexa as the generic equivalent. There was no taper or anything and she fared fine. My problem is that Celexa is not the generic for Lexapro and some doctors still refer to it as being the same med.
Nothing in my pharmacology reference books says you shouldn't abruptly stop taking Celexa, but I, personally, cannot tell you to do that.
If you've been having your prescriptions filled by the same chemist/pharmacist, usually if you go in and explain the situation to them, they will give you enough of your regular medication until you can see your doctor.
Unless it is totally different in Germany, if your doctor is on holiday, he should have someone covering his practice. Have you tried calling his office and asking the service who is on call?
The only other advice I can give you is to discuss this with a pharmacist who CAN tell you what you should do.
BTW................I'd be pretty concerned that your doctor back home wrote you the wrong prescription. That's a really huge screw up for a pharmacist to make. If he actually meant to change your medication, he sure as hell should have discussed it with you first.
Good luck
Greenlydia