Headaches

So I am 7w2d and will be going to the doctor Dec 23 for my first appointment. I have been lucky so far without many symptoms. Will get a little nauseous every now and then and tired at time. I have been sleeping 9 to 10 hours a night! My only concern is my HEADACHES. Is anyone else experiencing this. I am not s coffee drinker but do drink diet coke. I have cut back on drinkng diet coke since I found out I was pregnant and drinking a lot more water. I just don't understand th headaches?!?