If your toilet clogs, you can usually use a plunger to restore function. Simply flush the toilet one time and press a plunger over the opening. Create a seal and pump the plunger multiple times to move the blockage through the pipes.
If your sink clogs, you may be able to fish debris out of the trap using a drain cleaning tool. These are available at most hardware stores. Please do not use corrosive chemicals in your drain, as these could damage the pipes.
If your HVAC system isn't working properly, check your thermostat settings. Settings may be changed by accident. After verifying that the settings are still correct, contact your utility company to make sure there are no problems with your account.
Make sure your thermostat is set correctly, and has not tripped or encountered a fault that has shut off the system. Reset the thermostat. Call your utilities provider and check to see if your service has been suspended.