If i ovulated on 28th may and am now pregnant. (tested + yesterday). how many weeks pregnant am i? irregular cycles and last period was 7th may.

Depends: If you ovulated on May 28 then you also conceived within 24 hours of ovulation. So today you would be considered to be 4 weeks along. While only 2 weeks have passed since conception, pregnancy dating is based on menstrual dating which assumes that ovulation occurs 2 weeks after the last period starts. So you would be considered to be at 4 weeks gestation. Congratulations and good luck.