roller dave, you made a bad problem worse by driving it. i'll bet money the head gasket is blown. no amount of pressure testing is going to find this, but, when your losing coolant, and there are no leaks, any mechanic with half a brain will check the oil. the water from the coolant system is bleeding into the oil via the head gasket. by driving it, you probably warped the head. if you have a dodge ram like in your pic, you may be okay. it has steel heads. if it is a car with aluminum heads, that is ALOT of work. DO NOT DRIVE IT ANYMORE UNTIL IT'S FIXED!!!!!!!
hope it works out for you bro.