pregnancy and marching band ?

I'm a few weeks pregnant and I'm in high school marching band too. for the past two days I've been having really bad morning sickness. I threw up today twice. and I'm outside in the sun for about 4 hours. I play the baritone (about 25-30 pounds). by the time marching band ends I'll be 3 months pregnant... has anybody else been pregnant and in marching band? or is it a good idea to stay?