Hi kelbelle.
Yes, I know the feeling. I used to call the OCD thinking, 'looping' because the thoughts go round and round like a tape loop. I now believe that all worrying is like this.
I'd bet that the hypochondria is also part of the same mindset, I know mine was. We can't usually stop this kind of thinking, but I've found that we can put it to one side and do something else. It takes a good deal of practice though.
I've often thought that putting down these worries is like ignoring a pushy person who is upsetting us. When we first ignore them they get even more pushy, desperate for our attention, and that's often when we give in to them. But, if we can ignore them for long enough they eventually lose interest in us and simmer down. I think this is something like a cognitive behavioural approach.
I'm sorry that you are so embattled at the moment, and hope that it eases for you.
Peaceful thoughts and (((((hugs)))))) , M