5 days early AF

Lilly

so I'm confused, I've normally had a normal cycle all my life. this month AF was due the 28th. it came the 23rd or what I thought was AF came. It wasn't normal since I'm normally super heavy. the fluids were brown and dark red. they went from spotting to light back to spotting then gone after 4 days. I waited till this morning to test and got a negative. was this Af or was it implantation bleeding and did I test too early. been taco for. almost a year now. been to a fertility specialist and was told everything is normal and given prenatal vitamins to boost my body and help with tax. I'm so confused right now and so depressed I feel like giving up. please help.