Step 1, chill out.
People swallowed mercury and survived. They put it in their veins with a needle and it was fine. It doesn't go through your skin. To inhale fatal dosages, you need to work in an enclosed environment, where they have massive amount of mercury around.
"What if I break a thermometer or light bulb?
If you break a mercury thermometer or light bulb, a small amount of liquid mercury may spill out. Liquid mercury can separate into small beads, which can roll some distance away. The mercury may also evaporate into vapour.
However, this small amount of mercury is extremely unlikely to cause problems for your health."