is this implantion bleeding or af

hello i just had a question sorry if it tmi. i am ttc for about a year and half now. my af was suppose to show up on july 25th,2016 but it never showed up no sign of it but half way though july26th i notice a brown discharge but only when i wipe. than the next day it was a pinkish brownish never got heavy stay the same. it lasted about 2 and half days and stop for a day than came back.spotting still for a couple hrs than stop again. a week before it had started i had really sore boobs, really light cramps followed by very little spotting. and a bit of back pain. now today no spotting nothin i have a bit of back pain light cramps and feeling nauseous. also during the spotting i had no cramps or clots what so ever. af has always been on time never late. is this implantion bleeding or is it just af. i also have a heart shaped utrus which i know it will make it harder for me to get pregnant. any advice would help