Eggwhite CM at a random time ?

My cycles took a while to start back after I stopped the pill. They last approx 60 days since this summer. I had super stretchy egg white CM on 12/8 so I thought I ovulated (although not being "planned" by Glow but since it's irregular...)  but 14/15 days after, no periods and not pregnant. So I don't know how to spot my fertile window. Has it ever happened to u ? Thanks and Merry Xmas !