I suggest that rather than symptoms from Ativan, you are experiencing post trip anxiety. The Ativan may have masked the physical symptoms of stress, however your body was still under stress and as a result you now feel increased anxiety. It happens to me after every busy period of my life, regardless of if I feel stressed at the time or not. Also, jet lag and a let down after a fun/busy time can also be triggers of increased anxiety. After you return to your "normal" life, you return to thinking about how you feel in the moment more, rather than living in it.
Odds are good that you will soon return to how you felt before the trip.