So confusing

My husband and I had unprotected sex everyday during my low, medium and high times this month. We’re neither trying nor not trying and this is the first time we’ve not taken any precautions. I’ve been nauseous now for around 10 days, some days just for an hour and some days most of the day. I’ve also been so tired and having the weirdest dreams. My period is now 4 days late, they’re always very regular. I’ve done 3 tests now in the last 2 days (inc first pee) all have been negative. How late is late? Other than being bloated I’ve no other PMS This isn’t normal for me but when would it be considered reasonable to see the doctor? I do feel different but don’t know if it’s all in my mind. Never been in this situation before