Late period...

My menstrual cycle has been fluctuating recently. January- February: 28 days, February- March: 34 days, march-april: 29 days, april- may: 34 days, may-June 35 days. Now it's the 38th day and I still don't have my period. I took a test today and it was negative. My bf and I have been using a condom and we decided this month that he wouldn't ejaculate so I wouldn't get worried about my late period. However , i'm still super worried. What are the chances im pregnant?