I don’t understand

o I got my period for the first time last month 8 months postpartum. I got it 2 weeks after getting my first solid smiley.

I didn’t check for ovulation as I was travelling so I assumed I ovulated on vacation and was getting my period in the next couple of days. I tested today and got an empty circle. For some reason I went back 20 minutes later and tested again and got a solid smiley. What does this mean? Faulty test ? Late ovulation? Change in cycle length?

I also dtd 3 days before. Is there a chance I might be pregnant ?