Health anxiety

Just wondering if anyone has any helpful advice on how to deal with health anxiety... I’m constantly worried I have cancer/tumours etc or my children have cancer/ picked up some crazy disease when they get a common cold or flu etc. I’ve had to stop googling because I was driving myself insane with every symptom.

I’ve been reading a few books but if anyone knows of a good book, or something that helped them it would be appreciated. Also for the record I have started to see someone but only had one appointment so far, waiting for my next one. Thank you.