Why is my dog vomiting like this please this is the 2nd time shes vomiting like this PLEASE IM WORRIED

Dogs eating grass is actually quite common (it has been observed in wild dogs, too, and may be completely natural) and this form of pica does not usually cause too many problems. In fact, most veterinarians consider it a normal dog behavior. One small-scale study of 49 dog owners whose dogs had regular access to grass and other plants found that 79% of the dogs had eaten plants at some time. Another survey about plant-eating dogs found that grass was the most commonly eaten plant.

Why Is My Dog Eating Grass?
There are a variety of reasons your dog might be grazing on your lawn.

Some people propose that dogs might turn to eating grass when they don’t feel well as a way to make themselves vomit, and then feel better. Others dispute this idea, on the basis that dogs are not proven to be smart enough to decide to treat an upset stomach by eating grass.