Pains in my side above hip and weight loss

[jassylove123]

I'm 17 and was on the depo injection for around a year and a half I gained half a stone then the doctors wouldnot give it to me anymore as I lost a stone in 10 months while having the injection I suffered with headaches and pains in my stomache by my hip bone and have never found out why but I got the implant and I still suffer with the odd headache and the odd pain but not as much. I had to go to the doctors about loosing a stone while on the injection and had to go back 6 months later to find out I have lost only 4kgs and the doctors are being werid and want me to have a blood test but I don't understand why and why I'm loosing weight and having these stomache pains?? I also eat alot and most of the time it is fatty foods???