Hi, bringing up dark yellow phlegm with bright red blood streaks, no cough, no sore throat, no blocked nose. should i be concerned?

Bronchitis: Blood tinged mucus or sputum is often due to an infection in sinus or lungs. Many of us treat, unless bloody nose from blowing too much. Most of us will treat with antibiotics if it happens for more than 3 days. There are other causes, too, but it's a GREAT idea to get checked soon. In the meantime, avoid otc cough and cold meds, and fragrances and aerosols (which don't help, can make worse)

Bronchitis: No, don't worry. You are describing symptoms of bronchitis which we would expect to settle on it's own without the need for antibiotics. Only worry if you start to get short of breath or the amount of blood increases or if you continue coughing sputum & blood for longer than a few weeks.