So I have a question for everyone. A few weeks ago I got a positive pregnancy test and was so…

So I have a question for everyone. A few weeks ago I got a positive pregnancy test and was so excited. I called and made a prenatal doctors visit but it was a couple weeks out. I finally get to go to the doctor only to find out my urine test came back negative. I was so confused and hurt. They did blood work to test any hcg levels and just called me yesterday and said none were detected and I am not pregnant. 😔 however, I’m two weeks late for my period. I’ve had no bleeding at all and I’ve felt pregnancy symptoms for the past month. Yesterday I was so nauseous I could barely hold my head up. Is there still a chance I could be pregnant? Do y’all think they should have done an ultrasound to confirm?