Stomach Flu Stiff Neck I Have A Stiff Neck, Headache And Very Tired Last 5 Days...stomach A Bit Sick. Is It Flu Or More Serious?

I have a stiff neck, headache and very tired last 5 days...stomach a bit sick. Is it flu or more serious? - stomach flu stiff neck

I am a woman 36 years old and healthy. A little anxious to go, but no insurance on my General Pract. now.