Ok, so I never got morning sickness before really. sometimes I did. but I'm 29 weeks pregnant. today…

Ok, so I never got morning sickness before really. sometimes I did. but I'm 29 weeks pregnant. today I woke up, my stomach was not upset. And I puked without warning. it was just stomach acid as I haven't eaten in 15hrs. but then I spit up foam, bright white. it didn't feel like it came from my stomach. should I be concerned?