No sign of pregnancy

I’m here at this clinic as I have missed my period . I took a pregnancy test at home it came out positive and here I am at this clinic and the lady says she doesn’t see anything at all . I’m so confused that’s all the info she gave me : this place is pretty run down so I really doubt the validity of this . I should be about 6 weeks but she told me I’m probably 4 or 5 but usually I’m always on time with my cycle so I should be 6 weeks . They did a vaginal ultrasound as well and she said she seeing nothing . She told me to go Pee to help but usually they want you to drink water to help you see so idk . But I’m actually freaking out rn because I’m scared that it could be ectopic or something serious like this . Has anyone had this experience or any info you can give to help me out in this situation.