sick chihuahua (& other ?s)

Question
hi. i have a 7 month old chihuahua named rose, and she has vomited 3 times today.after she vomits she starts shivering.she is usually very active and right now isn't active at all. she has been sleeping most of the day.  i believe the vomiting may be because she's in heat and is bleeding a little from her "vaginal" area and is licking it too much as well. my mom believes it may be because she has been outside and she eats a little bit of grass and twigs. and finally, my bother thinks she maybe vomiting because he gave her a piece of a "hotpocket" (its like pizza). so we all have opinions in why she might be this way. do you think any of these might be the reason in why she is like this?and what can i do to fix this?... oh and i have some questions. when can she start mating? is she too young for that right now? i would greatly appreciate your help. thank you very much.

Answer
Dogs will naturally eat grass when they have an upset stomach to get them selves to vomit.  She could of have the upset stomach from the pizza then ate the grass to throw up. You should at least wait until your dog is 2 years old before thinking about breeding. Also there are a lot of things to worry about when a small breed dog is pregnant and goes into labor so you have 17 months to read up on it. Angela