Suggest Contraceptive Pill During Breast Feeding

hi Doctor

I had sex with my wife on this Sunday 24th oct. I was wearing condom. Unfortunately I had doubt that a drop of semen leaked from side of condom but not confirm. We had a 4 month old daughter who is being breast feeded hence we are avoiding oral contraceptive. Right now we are not planning for another. Plz advice any alternative contraception method as well as how to confirm whether there is any need to use oral contraceptive immediately.