Caloric intake and working all day in heat

Swmnmom

I will be working outside at a music festival all weekend. Today it will be for 8 hrs. Saturday and Sunday it will be 15 hrs plus. It is supposed to be 100 degree heat index all weekend. I will be helping load/unloading the bands equipment and bringing them to various locations on festival grounds. Some driving if they need to go off grounds for something. They feed us 2 catered meals so not vendor food. Questions: Do I assume I do not need a dedicated workout these days? And do I worry about what I eat or assume I am burning off any extra calories? I am a stay at home mom who is active with her kids but not any where close to this activity level.