EDD?

I had my period May 6-10 and it was really heavy. This was my first period since January 2021. May 18 I started throwing up and being really nauseous. May 19 I took a pregnancy test just to rule it out as I was still sick. It was positive. So positive the test line was darker than thr control line. I ended up taking 5 test. All the same darker test line then control line on several different brand of test. I went to the health department and confirmed my pregnancy on May 20, but they couldn't give me an EDD because they didn't believe me about my period dates, and she was rude about me only having 2 periods in 3 and a half years. Well I got into my OB on May 23. He was puzzled as well. They did a transvaginal ultrasound where they saw a sac but it was so small the machine couldn't give a measurement as to how far along I was. I go back June 12 for another ultrasound. I have been so sick. I've been in for fluids due to dehydration and I've tried Phenergan, zofran, and diclegis and still throw up. The doctor just called in reglan to try next. I had HG with my 2 previous pregnancies and this baby seems to want to follow suit. I just wanna know my due date so I can have a light at the end of this barf tunnel.
Anyone in a similar situation?