How to cope with being an overly anxious person?

HI All,
Most of you know how anxious I am, and you may be aware of my brain parasite post a few days ago. Well 4 days in and I’m terrified, I can’t eat, can’t sleep, every little head ache means I have the parasite.
I’ve rung the council and the nurse line, plus my friend is a Dr and she just laughed at the idea and sent me a photo of the creature in Alien. Very funny but it’s made it worse!
I’m not coping, I’m just waiting for symptoms of the brain parasite; due to perhaps not boiling the water long enough.
How do people cope who have high anxiety like me?
It’s driving me nuts, and today my nose is really blocked up and I feel just terrible.
The Dr has put me on Doxycycline for a low-grade sinus infection but I don’t feel any better, in fact, I feel worse.
I imagine I’d get symptoms soon of meningitis if I have the parasite so at least I’ve only got a couple of days to go and then I can stop worrying or start praying.
I really hate being like this – any help would be appreicated.