I'm so sorry! I 100% understand- I was so terrified and had to go through 2 weeks of feeling like I'd rather be curled up in a coffin. Did your doctor give you any warnings?? Mine didn't! Pissed me off so much. It definitely gets better though, I swear! I'm finally living now! I've got my first day of work this week, signed up every day classes for next quarter, I'm going to be volunteering, I can TALK to people now. I'm a completely different person and it's amazing. I still have a few of those times creeping up, but it's nothing in comparison. Sending you positive vibes, I hope you manage to pull yourself through and get to the light at the end!
Anxiety flare-ups are unpredictable and you won't get the full Z benefit until 8 weeks, so it could just be more fear fueling your anxiety instead of the med. Be cautious and observant is all I can say, other than I would stick with the 50 until you see doc.