Why does red light come on indicating low coolant?

What is your question?

Dash red light comes on - box with arrow pointing down & 2 wavy lines. Had coolant put in about a month ago & its already almost empty. Haven't seen any leaking. Someone told me it may need head gasket work done?

How long has your 2000 Saturn SL2 had this problem?

This is the1st time since having coolant put in a month ago.