You know an extreme amount about brain tumours. What this tells us is that you've researched heavily into your feared condition. That is a strong symptom of health anxiety.
My friend had headaches that came completely out of the blue. So bad in fact that he had to take off work sick. He was given oxygen to use whenever he felt them coming on and was off for two/three months with constant headaches. He had more than a right to believe that he had a brain tumour, but he didn't. After the two/three months they just went away and he's been fine ever since.
However, the anxiety in you made you believe that it was sinister. You've spiralled since, unfortunately.
What you had last night was a panic attack. They are horrible and I have suffered with maybe three of them in my life. 'Couldn't speak in your head' is what you described, that's because you were panicking.
It's easy to say stop worrying but I know you can't. That's why I advise you to seek therapy. Have you even seen a GP over these worries of yours?