"i am 18 yrs old, yesterday i went to my ob, to confirm if i am pregnant. so she conducted a transvaginal ultrasound. the ultrasound tells that i am not pregnant, i also ont have ectopic. how accurate it is? i am worry and thinking that i might be preggy because last month i have unprotected sex, i cannot determine when did i ovulate because since i give birth to my little boy (7months ago) i did not have yet my post partum menstruation. i am not sure how accurate is the transvaginal ultrasound result. few weeks ago, i experience some pregnancy symptoms. headache, sore breast, vaginal discharge, moving belly button (which i dont know why), bloated, and i thought my stomach is getting bigger. pls help me. i conducted home pregnancy test but it was all negative , my last test was yesterday also and it was negative. my ob did not request me to have blood test/urine because she said that the transvaginal result shows that i am not pregnant. is it enough to tell that i am not pregnant? how about my moving belly button and my stomach which gets bigger and bigger."

The transvaginal ultrasound and blood tests are about as accurate as you can get.
If they conclude a negative result then you are NOT pregnant.
You certainly wouldn't have "moving belly button and my stomach which gets bigger and bigger." at less than a month gestation !