implantation bleeding

so I now have been having regular periods since my miscarriage back n February and taking iron pills, so I have been ttc for a little while but no luck. So monday i took a test because I wasn't feeling well and it was negative so I'm wondering if I took too it early. Wednesday night I started having heavy bleeding and now it's almost stopped which is weird since my periods have been regular lasting 5-6 days. what does this mean?