Greetings, and welcome back! While it is true that we wait until 4-6 weeks to see if the medication is working, some patients note a positive change as early as 2 weeks. For others, it doesn't do much until 8 or more weeks. So, yes, it is quite possible the Viibryd is beginning to take effect for you. Why is it the Viibryd and not the Klonopin helping? Because the Klonopin hasn't changed much on the dose, and even with it present your anxiety still came back/broke through.
Hope this helps! Please let me know if I may be of further assistance.