Early pregnancy symptoms or pms?

My hubby & I have only been ttc for now going on 4 months, but I just have this inkling that we may have conceived. I have been taking hpt strips since 5dpo, and have gotten negatives each day, I’m now 9dpo, and my period is due in 4 days. Since yesterday, I am experiencing nausea with vomiting. heat flashes & extreme fatigue.. now I do normally get heat flashes when I’m experiencing Pms, but no nausea or vomiting.. has anyone else experienced anything similar?! What do you think?