Mid cycle bleeding

My husband and I are currently TTC, two prior miscarriages so were hoping that third time will be the charm! Im currently on cycle day 18 (5DPO) I stared spotting lightly and now its fairly heavy spotting, like a lifht period. I dont have any other cramping or normal period symptoms. Is it possible to get your period only five days past ovulation? Can implantation bleeding that heavy? Its definantly not my normal, whatever it is.