Fear is a funny little bugga
I don't suppose we should call 'fear' funny but my point is that you can be fine and feel safe but fear can creep up on you stealth like and BOOM it consumes you! That's what I mean when I say it can be a funny little bugga!
But when we are in this shitty breast cancer journey - wherever you are in the journey what is it we are fearful of?
Is it actually dying from the cancer? I think this probably rates lower than some other things.....
Is it fear of not being able to emotionally cope?
Is it fear of how your partner is going to manage?
Is it fear about work and keeping your job while you go through treatment?
Is it fear of feeling ill, the surgery and the dreaded chemo?
Is it fear of just not being able to do it, to be scared of being strong enough to manage 'everything'?
Is it fear of feeling fear?
So many things can cause us to feel the emotion of fear, but there are lots of things we can do to help ourselves when we feel the fear creeping up on us, before we are totally overwhelmed.

Initially just sit with the feelings, don't fight them which only makes them stronger and the response worse. Instead just be totally aware and accepting of what's happening mentally and emotionally. Feel where the fear sits in your body, this may sound strange but sit quietly with your feelings and relax, can you feel it in the chest area, the abdomen? Do you feel physically sick? Try and work out where the fear sits and just be aware of it.
A lot of times, fear takes over physically. It affects different people different ways. Identify if/how it affects your physical body and do the work to take care of your body. So if you hold stress in your back, you can learn stretches, foam rolling, etc. to avoid the pain
Trying to rationalise the fear....questioning carefully and non-judgementally what it really is that's making you feel the emotion of fear, locate the facts and place them over your feelings. Break it down into 'chunks', bite size issues that you can maybe work through easier!

Practice gratitude - sounds silly and maybe a little trivial but it's been proven to help emotional well-being. Just think of 3 things everyday that you are grateful for, I do mine at night before I go to sleep, they don't have to be big things, the simplest thing sometimes can go unnoticed but when you think about your day you realise that even though you may be going through a tough time there are always things you are thankful for. Gratitude helps shift the mind into a positive light, which overtime overcomes fear.