I'm terrified I have a brain tumour

Awhile ago, a friend of my mums was diagnosed with a brain tumour, a few days last I developed a slight headache. Straight away I am thinking it's a brain tumour and since then I cannot get it out of my head. I am a classic worrier and tbh it's really stressing me out, the headache in itself isnt exactly painful it's towards the back of my head and comes and goes for a second or two. It also occurs on the right side of my head, down the back of of my head and towards the top.
I've also had weird sensations in both arms but I have read up that could be due to worrying. I can still move them around and stuff. I have an appointment for monday to try and get some reassurance  but I was wondering if someone could try and calm me down and if anyone else ever gets ideas like this in their head? I try and tell myself brain tumours are really rare but it keeps creeping back