Should I be offended?

Hi beautiful ladies,

So yesterday, I went and saw my parents for Mother's Day. I don't have the greatest relationship with my dad, but I wanted to see my Mom.

*Backstory: I've had 3 miscarriages, and 1 ectopic back in December 2018. The ectopic almost killed me. I lost 3 liters of blood and my heart rate got down to 12 bpm in surgery*

Well, yesterday I met them at a restaurant. I got there first, and as they arrived my Dad greeted me by saying:

"Hey, Happy Mother's Day...oh wait...never mind..!" He then broke out into laughter.

Mother's Day is already such a hard day, but him saying that was like a punch in the gut. He's never joked about my medical issues before. I calmly told him right then and there that I didn't appreciate his joke. He turned it around on me saying that I was being to sensitive, and that I was making Mother's Day about me. Am I in the wrong for speaking up about how I felt right then and there, rather than stewing about it?

Any guidance would be appreciated.