Having continuous vomiting n fever on&off since 12 days, urine test shows serum creatinin :2.7, urea 108. has diabetes. is it serious any suggestions?

Yes and Yes: Ongoing vomiting in setting of fever and apparent dehydration that is significant enough to cause kidney injury -- as evidenced by a Cr of 2.7 -- in a diabetic should be evaluated in the ED.

Yes: Any prolonged vomiting in a diabetic is serious, as they can become dehydrated quickly. With the lab tests you listed, the patient is probably quite dehydrated already. See a doctor as soon as possible, as they may need an IV. Good luck!