[My lil friend]

Mina is a very well traveled pup. Many miles in the truck and staying in our trailer. We went camping (or as close as you get in a trailer) last weekend. We made the 4hr treck home,arrived Sunday evening,fed all 5 pups and an hour later there were three saucer sized puddles of vomit in my den floor,it was Mina. I was pretty sure that it was stress from what turned out to be a weekend of xpen time with frequent walks for the pups. My rule of thumb is 3 spells of vomit and we go to the vet so that is one. About an hour later Mina,Kenzie and I were falling asleep for the night,Mina started to gag,I jumped to the bathroom tile with her and she threw up 3 little puddles again. So that is two. The vomit was very wet,lite brown,not grainy,not mucusy. We all slept very well. When we got up this morning Mina ate,drank,pooped and peed normally,played chase in the backyard with Kenzie. Everyone ran and then came in for morning nap. While I was out my daughter called and said that Mina had thrown up again. She soaked it up with a white papertowel,by the time I got home there was a red halo on the outer edge,that is three and so we went to the vet. Noone else is sick and other than throwing up Mina is normal. No temp,no tummy pain,no refusal to eat.
Really strange unless you want to call it to much of a weekend. The pups had to stay in the trailer almost all of the time because it was wet and cold. We were attending an event so one of us would break away every hour and go visit and walk the pups. No new food,no water from a strange place,all meals were given on time.
Any ideas,suggestions?
She got a shot of Cerenia at the vets, is taking a med twice a day to coat her tummy and an antibiotic. If this occurs again shortly after all of this is done,we will be doing blood work.