What's happening 2 my body PLEASE HELP?

my husband and i had unprotected sex on the first day of my ovulation period.. (June 10).. starting just 3 days later i started having breast tenderness backaches headaches and cramps.. even til this day those symptoms are still are.. I've also been having nausea mood swings and I've been very gassy! i notice i had some a drop of blood Saturday.. but that was all.. i took a pregnancy test sun morning and it was neg. i was told it was 2 early.. this morning i had some bleeding like it was my period.. And it's enough 2 wear a pad.. but cramps and backache have stop. i still have the nausea and headache.. so can someone please tell me what's going on.. can i be getting my period and still be pregnant or what.. And if it help the blood at first was bright red and brown but now it's kind of dark but not dark dark red. also i had the mirena of 2 years taken out on may 12th and also i had none of these symptoms before i got my last period on may 31th.. please help