Spotting 2 weeks after period

I have pcos and my cycles vary in length. Last month i had the longest cycle ive ever had at 45 days and the period that followed was light compared to usual and only 3 to 4 days where they are usually 7. Now 2 weeks later im having brown spotting and cramping with back pain. Could i be getting another period since i didnt have a full one 2 weeks ago or has anyone ever experienced something like this being late ovulation and this may be implantation bleeding?