Heartburn as a first symptom?

So I'm 10dpo today, fixing to be 11dpo. At 4 o'clock I had some yogurt and oranges. At 7 o'clock we had manwich and about halfway through dinner I started getting really bad heartburn that I NEVER get. I couldn't even finish eating. Honestly I didn't even really know what it was until I asked on here in another post since I don't think I've ever had it before. It's even worse now as I'm laying down and all I've had since dinner is water