How Can You Be Sure You're Having A Cryptic Pregnancy

How can you be sure you're having a cryptic pregnancy when a doctor doesn't even consider it themselves I was healthy about six months ago I was checked for pcos I had no cyst or tumors I was on birth control when I believe I conceived my timing was off I didn't take them at the same time everyday I was on antibiotics now it is three months later I'm still having a period but it's way lighter and only last for three days I have pain in my breast my stomach is hard and certain food taste bland I have dizzy spells and headaches and I'm always fatigued which is unusual because my thyroid medication has always taken care of things like that and my dosage was not changed I've found a heart beat in my stomach with a Doppler I'd be around 16 weeks and look pregnant any suggestions