first off all stop running the car, you dont want to warp anything that wouldnt be to good at all , now when you say wont blow hot air, you mean the air is cold or there is no air blowing atall because its very possible that the thermostat is stuck closed and isnt allowing any coolant to flow in you heater. check your hoses see if they are warn or if there seems to be any fluid in it. the waterpump isnt a hard install at all , at least i think so but its up to how inclinded you are, the waterpump might also be the issue and is probally the most likely cause, im almost 100% on that , since you were on the freeway at high speeds it might have failed .if the pump is bad theres no coolant flow and no heat so good luck