Is she being unfair?

So I'm on my period and my cramps are unbearable.  I've been up since 4 crying and curled up.  Long story short, my mom has a lot of errands and a dentist appointments today.  I asked if I could stay with my aunt who's home today, instead of going with her and suffering.  She said that since they're calling for storms, I have to go with her.  What should I do?!   The cramps are terrible and I feel like I'm going to pass out.  Anything I can do to make it better?