Tiny blood streak particles in sputum.

Hello doctor, Recently, I had cold and cough. I had stuffy nose which stayed for 3days and throat burning for 2days. I had fever also for a day. Now, I have only cough. It feels like mucus is accumulating in my throat. I don't have any other symptom. Yesterday, I had seen some blood particles in my sputum in the morning after waking up. Though, I had coughed little forcibly to clear the throat. Today, In the evening, I saw it again few tiny blood particles like in sputum. Is there any serious issue ? I had only taken paracetamol(2days) , cough syrup (first 2days wet cough syrup and dry cough syrup for a day) and montair-lc(for 4days). I am not taking any medicine now. Please advise me if i need to take. Thank you.