Severe symptoms with #4?

Hillary • June 2020 👦+ July 2022 👶👶 + June 2025 ?

I barely had any morning sickness with my first 3. We're having a surprise #4 and I'm experiencing extreme morning sickness, headaches, and fatigue at 6 weeks. My last was only two years ago, but now that I'm 35 could this be age related? I'm miserable and it's freaking me out.