Okay, you may not want to hear from me, since I am only fourteen going on fifteen, but I don't believe you're pregenant. I do tons of research online on the subjects of health in young women, and emotional health (though that doesn't really have much to do with this situation). I have found several cases where young women have 'discharge' from their breasts. If it is yellow, or brown, or a darker shade it could be an infection. If it is light colors, or a milky color, then it is probably nothing to worry about. If you are this worried about it however, maybe you should talk to your doctor, even if it is only over the phone, for reassurance.
As far as the way you are reacting to it so irrationally, I would guess you maybe just feel guilty about skinny dipping with your boyfriend. If the closest you got was to hugging, then you couldn't be pregnant. I hope I reassured you, if not I am sorry.