What is wrong with my Jetta?

Hi, I recently bought an 09 Jetta 2.5 SE with 143k
and the coolant seems to disappear from the
resivoir pretty often, like I have to refill every
morning but nothing is really coming out under the
car it’s always dry and it never overheated at all, I
just get a red coolant light flashing at me when the
water is low, can someone tell me any info? Help!!