Likelihood of pregnancy

So I made a mistake 5 days ago. I was in my fertile week my boyfriend and I use protection well I told him to put a condom on he did however he told me he finished in the condom. Well I was doing laundry today and found the use condom in my laundry basket. Now I’m scared about pregnancy!! What is the likelihood of getting pregnant the day of ovulation? When I found it he still swears that he came in the condom. I think he took it off in finished inside me. Because after he said he came in the condom he went back inside without one on. I’m not on birth control so I use bbt and opk as birth control. After this mistake I am getting on birth control!!!! Finding an empty condom is what made me believe he came inside me and when i stood up i felt something dripping out he tried to say that it was my fluids. I do trust him but we both was drinking that night.