Leaking brown fluid from her virngal area and not eating much

Sounds to me like she is in heat. I know that when my min pin is in heat the blood looks brown and she is a crabby dog and doesn't want to do much of anything

Could you give us a little more information?
How old is she, is she spayed?
How is her attitude, normal, happy or sluggish and depressed?
You say she is not eating much, how long has this been going on?

If she is an older dog who has not been spayed? It could possibly be a uterine infection or pyometra.