What Causes Severe Thirst, Fatigue And Depression?

Hi I am a 23 year old female and for the last 4-5 months I have been very tired, thirsty, drink a lot, weeping a lot! And it s not me as I am normally very bubbly, never tired like I am now?? My dad is diabetic so I went to the doctors last week and they took a blood test and said I wasn t diabetic and just need abit of help?? Thankyou