Chemical pregnancy question

I had a YES test a few days ago. Then a NO and a few dollar store positives. I started bleeding went to the ER & they told me that neither my urine or my blood had any HCG left it in and that my levels were so close to zero it didn’t matter. So I’m still throwing up and stuff and I test again with a dollar store test and it’s positive. Read within the time frame and everything. So confused.