Pink spotting

Ashley • I`m 28 yrs old. Just celebrated my 10 yr. wedding anniversary. I have two girls ages 7 and 8. Just started TTC for #3!
My opk tests were positive on the 20th (evening)-22nd and negative today on the 23rd. Me and my husband did it on 20th and 21st. I had stomach cramps 20-21 but did not yesterday. Now it's the 23rd and having some cramps and when I wiped this morning there was a small amount of pink. What does that mean?