Should I use back up birth control

Patient: Hello, I missed a birth control pill Thursday last week so I took two pills that Friday. Last night I had sex on the last day of my package of pills. He was wearing a condom but because there was alcohol involved I cant be certain if it was kept on the entire time. Yes I understand that was an irresponsible desicion but it was a mistake. Would I have been protected or should I take Plan B? (Which is pricey so I dont want to take it if its not necessary) Thank you!

Symptoms: Anxiety

Doctor: Hello,If you have been on birthcontrol and had sex on the last day of the pack which was protected , it is unlikely t hat you would get pregnant firstly because there had been no condom rupture or misadventure and secondly being the last day of tricyclen lo pill, you are expecting a withdrawal bleed.So it is advised that you wait for your withdrawal bleed and there is no need to take an emergency contraceptive pill as it may unnecessarily delay your cycle and disrupt the cycle.I hope i have answered your query,wishing you health,regards