My 3 Year Old Started Vommitting At 3 Am Then

My 3 year old started vommitting at 3 am then started a high body temperature in the afternoon for 2 days. in the same day her temperature got normal she has a brown smelly dirt like stool then she vomitted. on the second day she had a very soft white stool i am not sure but i might have noticed blood.
ps she had no apetite for any thing all she ate was yogurt
she has a history of constipation due to holding her poop in since she was potty trained