Is there any damage that could be caused by insufficient coolant ? I never noticed the temp needle to be higher than before...

Its probably been like that since I changed coolant a couple of weeks ago. I already put it way more coolant than the specified amount but still seemed to suck it all up

 

As long as your car didn't overheat, you are good to go. Just keep filling it with 50/50 mixture until the system stops draining the tank. When you refill your car with coolant, you have to keep the heater on and let the car get up to temp. Also, leave the cap off while you are filling and keep filling until you see no bubbles coming out the top of the radiator. That way you fill the empty heater hoses with coolant and you have no air bubbles in your system.