My Daughter Is 4 Years Old And Had Suffered From

My daughter is 4 years old and had suffered from constipation since she was 3 months old. I'm not sure when her last bowel movement was but it's been awhile. The whole household has been sick with something viral for 2 weeks now. Today my daughter started vomiting. She's plenty old enough to respond to urge but instead she just lays there and wallows in it, sometimes choking on it. It smells his awful too, like poop! I noticed it was the food she had eatten 5 hours prior to vomiting. Is this a sign she is way to constipated and should see a doctor ASAP or is it just a new symptom of this viral thing?