I had my lmp 18/11/14 don't know when ovulated had unprotected sex 15/12/14 ttc had light brown spottingnot enough for pad period or inplantation37day?

Spotting : The only thing regular about menses is that you can occasionally have an irregular cycle. That may mean a lighter cycle, later cycle, etc. Any change in stress, diet, weight, exercise can effect this. This could be a period, or you could be pregnant. I recommend a home pregnancy test, if negative and continued abnormal cycles, seek care from a local provider