Thigh cramps

Any idea how I can be having a muscle cramp in my thigh/hip I have had cramps in my calf every now and then but now I have one in my thigh/ hip anyone have any ideas

I'm only 18 and I'm not pregnant and I drink water basically by the gallon and I have a pretty good diet and I do a bit of walking for my job but I don't think I did enough to over do it with it