Help!!

How do you tell the difference from your period and implantation bleeding? I usually always have cramps when I'm going to start af and today I woke up and went to the bathroom and it was like a pink sticky discharge. I have been tired, nauseous, moody, my boobs have been extremely sore and I have hot flashes constantly. I have taken 2 test this week and both bfn. What do I do?