Nothing to worry in case of occasional nasal bleeding . If it occurs regularly then you need to consult for work up to diagnose the underlying cause

In this case you seemed to be having cold symptoms since one day and had one episode of mucus mixed with blood.That might be due to minor trauma in the nasal cavity due to repeated blowing of nose . This can be considered normal as it happened only once but in case this happens again detailed medical evaluation will be required .Your present symptoms and past medical conditions will need to be further evaluated.

Kindly consult for your concern

An isolated incidence of blood in mucus from the nose is not significant but a recurring episode needs proper evaluation. If it happens again then you should consult with an ENT specialist in your area.

If it is one episode of blood in mucus, no need to worry, if it continues you requires further workup..