sex revealed brown blood?

Jessy
My husband and I were having sex and then he says "hey there's blood" and it was brown and in small clumps. I hadn't noticed this until he said that and I haven't gotten my period. Also my period has never done this before. 
Has anyone ever had this happen? Is it implantation bleeding? I took a test today before he noticed this and it was negative but after seeing the brown I'm guessing it was too early to test?