A little nervous

Hubby and I had unprotected sex on Sunday and he came inside me accidentally. I had just finished 5 days of abnormal bleeding that came 2 weeks after my normal period. Because of the abnormal bleeding double period thing idk when I should expect my period. Hormonal birth control does not agree with me and I don't want to take plan b. glow said 3% pregnancy chance - does that sound accurate? Do you think I'm safe? We have an infant son and I def am not ready for another kid