Ovulation or Pregnancy?

Sydney • TTC baby #1 at 21
Ok so I have had sore nipples since the day before I believe was my ovulation. ( I bought my ovulation tests a little late.) my cramping started at 4 dpo and is still doing I am now 7 dpo. I took my ovulation tests yesterday and today and today is lighter then yesterday so I am assuming I am coming off my my fertile week. Is there anyway this could be pregnancy cramps? It's right in the my mid abdomin and hasn't been one sided during this process I also have lower back pain.  I had right pelvic pain during cycle days 11-13. Please help me!!