I regularly get nosebleeds roughly once a day, for about a week, twice a year (during each seasonal change). They usually last 5-15 minutes, depending on the humidity of where I currently am (ones in the shower take horrendously long).
If it's the same story for you, I wouldn't worry too much about it. I've been having the damn things since elementary school and they don't seem to be anything more than a nuisance. Otherwise, yeah, it might be worth a trip to the walk-in clinic.
Out of possibly related curiosity, have you been knocked upside the head lately? It could be a symptom of concussion if so.