Posterior nosebleeds or something else?

I’ve been getting minor nosebleeds for about two weeks now. When I say minor, I mean it’s never serious enough to even make it out of my nose. But, typically in the morning, I voluntarily cough up phlegm and there’s sometimes streaks of blood in it. It’s never a lot - in fact, the worst of it was also around the time it started, and that was only directly AFTER the worst nosebleed so far. It’s weird though; any mucus that comes from my left nostril is almost always red. Dark red and crustier usually - implying that it’s old. It’s only ever bright when I pick my nose due to irritation, I’m assuming that’s why it starts bleeding😮‍💨

I work outdoors, and I don’t sleep with a humidifier. It’s cold out and the air is dry, and I have my heat on at night. The nostril is question is typically dry as hell.

I know quite literally everything points to a posterior nosebleed caused by dry air, but is the frequency normal? Does it make sense that it would last for about two weeks? I read up and apparently these can be caused by some kind of terrifying conditions as well. Has this happened to anyone else, is it normal, and when should I worry?