Could I be pregnant?

I feel stupid even writing this as it could all be in my head but that 10% is nagging at me.

For the last 3 months, which is the last time I had sex during ovulation, my body has completely altered- meaning I have ZERO PMS symptoms when I always get very sore breasts etc- my period has been watery and much shorter than usual.

I have taken hpt tests all negative. However I am only just beginning to feel nausea, dizziness. I have booked a private ultrasound on Monday not just to check for pregnancy but I have other issues which need checking anyway.. but I just can’t get these strange changes out of my head something just feels off and I know everything points to a negative by normal standards, including the fact that I’m 39. The odds are very low. Can anyone give any advice if they have had regular but changed periods and negative urine tests?? I have no children and this would be a miracle blessing for me but I don’t want to shatter myself with too much hope :(

I feel very alone.