Could Something Be Wrong When I Had A Positive Pregnancy Test But Then Bled Like A Normal Period And The Ultrasound Showed No Baby?

Hello doctor, i would like like to ask, early February this year, i had pregncy symptoms then I bought 2 pregnancy test, both came negative, then because I was still not feeling well I went to the clinic, they took some urine test then they did a pregnancy test which came positive then I was told I have to start attending doctors appointment,few days after doctors confirmed I was pregnant I began to notice there are spot of blood on my panties I took it lightly , a day after that I began having my normal periods, I rushed to the clinic they did pregnancy test again then results still came positive. Yet ultra sound showed no signs of a baby on my womb. I had my periods for 3 to 4 days then they stopped till today, could there be anything wrong with me?