Why has my bruise gotten worse after 2 weeks?

[Rachaelv00]

I have had a nickel sized bruise for over 2 weeks now, left arm, from nothing. It wasn’t changing, it was a light blue/grey color. It was never concerning I figured it would eventually go away. I bruise easily, and frequently have bruises from nothing. A few days ago I woke up and this bruise all of a sudden go extremely dark and a little larger.  Over the next few days the bruise has gotten significantly bigger now 3 times the size and extremely dark. I have also noticed there is a lump on the side of it (outside of the bruise actually), the bruise is also spreading down along the course of my vein. I’m assuming because that’s how my blood flows. I understand how bruises heal/the coloring it goes through. I’m a very still sleeper and there is honestly nothing I could have bumped it on in my sleep. I have never seen this, I cannot find any answers online.