Does my older dog need a booster vaccination in 4 wks?

I took my Chihuahua who is 2 years old to the vet today for a parvo and distemper shot. I was told they only give a 6 way so I had it done. Then they told me I had to bring her back in 4 weeks for the booster. I thought only puppies needed a booster. She got very sore when we got home to the point for not being able to walk on her leg where they gave her the shot and yelped in pain if I touched the area. Now she seems to not be as sore but is throwing up. I think she will be ok but I don't want to put her through this again. Does she really need a booster??? Also this is a military vet clinic and I know they have stricter rules they go by.