Possible pregnant

The app says I ovulated the 20th. I took a opk test on the 18 and it was low, took one on the 19th and it was high. Had sex only on the 17th and 22nd. I had just small cramping 4-5 days after my ovulation and it stopped. No spotting. I’m four days away from starting my period. I’m having hot flashes, nausea, fatigue, and have had two dreams I took a test and was pregnant. I’ve only had pregnancy dreams when I found out I was pregnant with my son. Has anyone got pregnant from having sex before ovulation?? I really didn’t think we had a chance this go around due to not having sex on or the day before/after ovulation.