Imgeha, your therapist would not be putting you into a sonambulistic trance (like you see in stage shows), they should be directing you to deeply focus on the therapy or direct suggestions in order to override your current hypnotic state of anxiety.
Health anxiety phobia/OCD is very much like fear of flying in that there does appear to be a tangible risk, I.e. That the plane could crash or that you could be having a heart attack. However, it's all about probability and accepting the amount of control we have over not missing any critical signs. Of course it really doesn't help when hormonal adrenal rushes are creating very frightening palpitations etc. but understanding their cause should just leave you uncomfortable, not in fear of a true heart attack for example.
In order to get rid of your old habits, often copied from parents with the same condition, you need to accept you cannot be aware of every single neuron change that might lead to disease. Scanning constantly is exhausting and puts you in a hyper alert state where will actually cause symptoms to increase. Instead, force in new habits of being rational about your symptoms and fears until they become your new habits. It will feel unnatural and irresponsible, when you've been ao over vigilant, but it's also freeing yourself of unnecessary responsibility.
Re. the thought of suicide to get rid of the anxiety, this is not as crazy as you think! Your brain is so exhausted by trying to second guess what might happen that this feels easier and a relief. However, by getting to this point it means you have accepted the worst part of your fear, I.e. Dying, as inevitable, so just accept that will happen one day but that by focusing so much on it is taking away your ability to focus on living.
Therapy can help you to get to the main cause of your fears, for some it could be the pain of death, for others it could be leaving your children alone, for example. Then the therapist can rationalise your fears so that they no longer have the overwhelming power they have over you now.