spotting, AF due 1/3/18

7dpo-8dpo I believe, we aren't trying but AF isn't due until Jan 3rd and light cramping like I was gonna get AF all day yesterday and randomly today. Had brown spotting yesterday morning and now have this. Creamy and some random stringy-ness. Tender boobs,tired, and constipation. Thoughts? We have a 6 and 3 year old.