I Have A 2.5 Yr Old That Is Not Feeling

I have a 2.5 yr old that is not feeling well. Sun she ate a little and then threw up... after a couple hours she seemed normal until Sun evening more tired then normal and at night had 102 fever. After that no fever and she hasn't felt good often thinking she needs to vomit. Eating less....haven't been able to get her into peditrician & urgent care was full. Ideas?