I had unprotected sex with my boyfriend and took the morning after pill within 12 - 14 hours, I thought I was meant to be ovulating at the time but maybe I miscalculated it cause I have a longer cycle, 2 -3 days after taking the pill I've been having symptoms of ovulation, is there still a possibility of becoming pregnant?

OF course you know that the morning after pill is not 100 percent effective. So yes you still could, but the odds are very very low