I liked this thought it would be a positive thought

Opposing ideas can both be true. It's true that nobody knows what you're going through and, as @Jenv said, nobody is going through it with you. And it is also true that there's a different effect on people who go through breast cancer alone versus those that have a network of supportive family and friends. And it's also true that spouses and children and other loved ones can be massively affected by a breast cancer diagnosis. And it's also true that there are insensitive shmucks out there who will say all the wrong things  :s