Is this a brain tumour, or worse brain cancer!?

Cancer, especially a brain tumor or cancer grows extremely fast . . if you had cancer every one would know it by now. Cancer is a progressive disease which means it starts as a single microscopic cell that loses the ability to stop growing. What this means is that the cell will grow very fast by replicating and multiplying until it is a tumor and the tumor will grow very fast too . . weeks to months . .not years. In the case of a brain tumor they grow fast and there is no place for them to go . . they can be seen because eventually the push out through the skull. It is doubtful that you have brain cancer . . . but you should go back to the doctor to be checked for the migranes . . it is possible that the migranes are being caused by a flood of hormones normally brought about by puberty. You should get treatment for the migranes.