Weddingbee boards

I'm a natural blonde (not super light, more of a dirty blonde) and want to try coloring my hair dark brown.

I don't necessarily want to use a "permanent" dye and have to wait for it to grow out. I've used permanent color before, and it took almost six months to fade/grow out completely. My wedding is 6 months away, and I want my natural color back in time.

I was thinking more along the lines of one of those dyes that last through 28 shampoos. But all of them say on the boxes that you should not go more than two shades above or below your natural color. I'm worried that if I try to use a much darker temporary dye, my hair will end up a much different shade than I intended.

Does anyone have any experience with this, or can recommend a brand that you've had success with? Or am I just out of luck and need to wait until after the wedding to try this out?