Tmi vomiting

Rebecca • Proud mommy to Lily, August 2015. Expecting #2 due December 2020.
I'm 31+2 today. I haven't been nauseated at all since 14 weeks or so. I've had a great appetite and everything has been great. Yesterday was no different. I ate and drank plenty, went to work at normal, had dinner about 9pm, and felt perfect. Then two hours later my lower back for a little more sore than it has been, DH tried to rub it and I instantly felt like I was going to be sick and couldn't keep it down. After getting VERY sick I felt fine, but wondered what caused it. Do any of you have any experiences similar? 
I had no abnormal swelling
No cramping or contractions
Felt fine quickly so I don't think it's a stomach bug
DH felt fine so I don't think it was the food. 
I have bad heartburn but I took Pepcid before eating and have had it break through the medicine so many times before and been fine.