How badly is my car stuffed ( i think head gasket is blown ) symptoms.?

yes it is possible that it is not a head gskt. it could have been just low on water ,and also if it has a blown head gst it will over heat on you in a matter of a couple of minuets.also a head gst will make a white smoke come out the exhaust .if your car isnt doing these things mentioned you should be fine maybe a t-stat or something small.