Help, confused!

Tamar • <3
I've been on nuvaring from October until the 6th if jan, started bleeding from 9th-13th jan. Spotting for 4 days from the 16-19th jan. Had unprotected s*x the 18th, 22nd and today 31st. OPK was positive both the 18th and today the 31st.
 I have been having cramps since the 30th and very sore nipples today. Did a HPT today, negative :( Could I be preg? Or just ovulation? No o CM today , saw CM the 18th only , with the spotting. Please advise me..