Yes, you may be suffering ativan tolerance.
Not a good time to decrease ativan. Wait a while to stabilize. You do not want to suffer WD ISRS + WD BENZO (=would be terrible).
While stabilizes, you can get information on the benzo WD · "Dr. Ashton Manual":
http://www.benzo.org.uk/manual/
Benzo Forum:
http://www.benzobuddies.org/forum/index.php
Hugs