Orange coolant, especially if its been diluted down by water isn't in itself too much of a concern. Its not unusual to see a sort or 'mayo' or emulsion in the coolant bottle this time of year if the car tends to do short journeys either. If you are losing lots of coolant internally you would expect to see it exiting as steam in the exhaust. Again this time of year a little steam is not unusual esp when cold.
Its more likely you are losing water from the waterpump or maybe thermostat, have a look down the left hand side of the engine (looking from the front) and see if you can see anything. With the rate of loss you are describing there should be plenty evidence.
Maybe check the oil level as well to see if it is working its way into the sump.
Hopefully its not the worst case of blown head gasket or failed EGR cooler.
