Cryptic Pregnancy? Or Undetected?

I got 2 positive hpt and that was after my 2nd missed period so 2 months in, I had recently got my blood and urine taken at the hospital but results were negative? But I'm now 4 months late, a growing or bloated tummy, I had bad headaches now they have subsided, nausea, dizziness, increased appetite or no appetite at all? Mild cramps, etc. I have had unprotected sex every day for months with my SO, this has never happened to me and NO I didn't want to be pregnant so I didn't give myself symptoms or my implantation bleeding 🙄 your thoughts and stories?