tolerance builds with benzos, like any other drug. You could try to taper down for a bit till your regular dose works more, or up the dose. Increasing the dose you'll just run into the same problem down the line and have to increase it again.
Taking benzos as needed is a much better option than everyday use, but for a lot of people with severe anxiety, this really isn't an option when other methods don't work.
You could also switch to another benzo with a longer half life, so you get results over the whole day.