female lab

Question
i have two labs , brother and sister in same yard. They are 10 mo old, yesterday female began acting very lethargic, warm nose, loss of appetite, when she drinks water she throws it up shortly there after. does not throw up any other time. when she goes to the bathroom nothing different in stool that i have seen. not sure because brother shows no symptoms at all. ????????

Answer
She really needs to see a vet.  It is hard to say if it too serious to let go until Monday or if you need to find emergency help.  Has she had a full round of shots including 6 month boosters?  If so, it is less likely to be life threatening if you wait.  

With only one of 2 dogs being sick, it is possible it is something she ate.  Young Labs are bad about finding and eating things they shouldn't.