period 2 weeks late! could she be pregant?

Can someone give me advice , im currently in a relationship and me and my boyfriend are trying to have a baby. We had sex on ovulation and couple days before ovulation , 2 weeks after I was walking and discharge came gushing out like water down my leg, later on that day I went toilet and wiped and there was light pink discharge this has never happened to me before , then the next day I started bleeding seemed like a period but thought the pink discharge was implantation bleeding , I took a pregnancy test it said negative however it could be to early so going to wait , I had symptoms of pregnancy but does anyone know what this is ?