Am I crazy?

My husband and I BD while I was ovulating. Not actively trying to conceive but I knew I was ovulating. Now I’m 4 days away from my period and I’m losing my mind. I’ve been so nauseous since last Wednesday, every morning. And especially if I don’t eat anything. My breasts have been a little tender but not like when I was pregnant with my daughter. Some mild cramping. My cervix has been high and soft till this morning, it starting to get firm. I’ve taken First Response 6 days sooner and it’s come up negative. So I have it in my mind that I’m not pregnant. But every morning like clockwork I start to get nauseous and feel dizzy at times and it makes me think there’s no other way. I’m never ever sick like this. Is it possible to still get a negative test this close to my period?