Diziness fainting and headache. Sex!

I did unprotected sex on 5 April 2025 2 days before my next cycle probably 66 days ago and took emergency contraceptive pill within 2 hours and 10 days I got bleeding like my periods but heavy and lasted 3 days as my normal days in periods on 19 may I got periods but it was 4 days late it had less bleeding than my periods but with a lot of clots  I did multiple pregnancy test and beta HCG test and USG pelvic everything was negative for pregnancy on 6 June I got episode of fainting dizziness and shortness of breath and shivering then I became ok after an hour then on 10 June I did serum beta HCG urine pregnancy test and USG pelvic all clear for pregnancy but today but I have headache sometimes like sometimes heavy and today I again in evening I had episode of fainting dizziness and shortness of breath...I want to know that is this because of harmonal fluctuations and imbalance or these are pregnancy symptoms and I am pregnant with false blood and urine test after 65 days of unproted sex