If the clutch fluid is pulling from the brake reservoir, and a bunch of it leaked out, you may be very low on brake fluid. In stop and go traffic, it is the 'stop' part that is the most important!
Of course, with no clutch, it is pretty tough to get going so you need to stop. Can be done though. I once made it home 120 miles with no clutch release in a Volvo. You have to plan your route to avoid uphill stop lights. People tend to honk at you when you push your car to get it rolling at stop lights.