Finding my potential child

Hi folks,

I had a one night stand about 20years ago, I was 19 at the time, met someone from I remember she was around 30 at a nightclub. We had unprotected sex, no phone numbers swapped and I went home afterwards. I always had a strange feeling about that moment, Like any young man I would be out and about all the time. I remember seeing what I thought was the same woman about a year later wheeling a buggy into the local pub that was attached to the nightclub where we met. I wasn’t even sure if it was her but I ran out of the pub.. I never returned back to the pub again. I can’t be sure if it was the same woman but I always had this strange feeling. I moved away from the area, I know I’m not a nice person if it was, I was young, naive and stupid and I regret not saying something the time but it’s always been on my mind. Again I’m not 100% sure but I would like to find out if I am the father, I wouldn’t know where to start.. if anyone who has experienced something like this..