Hair color emergency?

I'm 23 years old. I've been dying my hair on my own since I was 13. I usually experiment with different shades of brunettes. My hair was a medium brown with lots of caramel highlights. I wanted to dye it an all-over dark brown for the winter. I used Nice and Easy Medium Ash Brown. I was stupid and forgot to make sure the color in the box matched the outside of the box. I'm pretty sure the wrong color was inside of the box and my hair definitely came out way too dark. It's so dark that I can't tell if it's darkest brown or black. In the bathroom lighting, I can see brownish tones, so I'm thinking that it's brown. Either way, it's too dark. My hairstylist said she can do a shampoo cap to strip the color and then I can re-dye it. But that's money I don't want to spend and damage I don't want to do to my hair. (I have curly hair, so it's naturally dry. Plus I dye it every 3 or 4 months, and I don't want to damage it anymore.) I washed it a few times already with Prell shampoo, which is supposed to fade the color. It did nothing. What can I do to fade it a little bit before Thanksgiving when I'm going to see my whole family and lots of friends?