Ewcm from 20th 23rd jan with litght cramping. but no change in bbt. have i ovulated?

Most likely: Egg white cervical mucus (ewcm) is a type of cervical fluid that is produced right before ovulation, during a time when you are most fertile. Although it is not always true, women in their twenties will have around 3-5 days of ewcm and woman in their thirties may have only 1 or two days with ewcm. Given your last day of noticeable ewcm was 5 days ago, ovulation most likely has already occurred.