How Do You Ever Confirm Cryptic Pregnancy If The Doctors

How do you ever confirm cryptic pregnancy if the doctors don't believe you that's something that is really hard to deal with my symptoms are vomiting, headaches, lower back pain, I have this nasty taste in my mouth that comes and goes depending on what I eat it's on a daily basis I have already taken a pt which was negative I'm gaining weight my stomach is getting bigger please I need help