What are my chances?

My period has been irregular starting at January it was 28 days, then 34 days, then 29 days, thsn 34 days. Now it's already my 34th day in my cycle and no period. I had sex with my bf 4 days after my period ended but we used a condom. Took a pregnancy test today and it was negative. Im hoping im not pregnant, but what are the chances