1998 Chrysler Sebring Blown Head Gasket

Ok about a month ago my 98 chy sebring overheated. So I checked the coolent and it was low for the first time in 2 years so I filled it up. And It
ran ok until now. Last night my car started smoking REALLY BAD (white smoke im sure) so I checked the iol and it was very low and I just filled it the day before and I put an aditive in it called no leak $7 because I had a very little leak 2 drops I took it home and went to bed. The next morrning I turned on the car and I heard a clicking sound about every 10 sec. So I turned it off and left it. I checked the oil and there is nothing rong with it not foaming or anything but my coolent was low again about 2 cups and the resevor was empty. So is this a blown head gasket and if so how hard is it to do it your self and would I need any special tools to fix is