I am 12 weeks pregnant and have not had any vomiting until today. do i need to be concerned that it started this late in pregnancy?

No: Not unusual to start nausea or vomiting @12 weeks. What is important is the freqency of vomiting, intensity, quantity, and color of the and the color(green, yellow, coffeeground color, any any shade of red. , are you taking replacemnt fluids.Severe prolonged vomiting can put you in the hospita for rehydration and recovery.

Not necessarily: It is not necessarily bad - continue with small, frequent meals and plenty of fluids. Nausea could also be a sign of other illnesses such as bladder infections - if it persists or worsens with fever and other symptoms see your doctor.