You dont say how long it has been since your diagnosis, whether it is recent or if you are post active treatment, however it might be worth you contacting your breast care nurse to see if they can arrange some counselling for you, if you have a MacMillan centre near you I think they offer this service are well. Additionally have you spoken with your GP about how you are feeling to see if there is something they can do to help you. I dont know if you are working, but another option if you are, is to investigate if your employer has a confidential counselling service that they can refer you to.
I had six session of counselling which started just before I commenced radiotherapy as I was struggling, it was the best thing I did, I was able to talk to someone who did not know me, could discuss the way I was feeling objectively, it was a safe comfortable environment where I could be honest about the way I was feeling without fear of upsetting my family and friends.
It is not unusual to feel like this, we are having to deal with so much once we are diagnosed and subsequently following active treatment then trying to get used to a new "normal" it does take time, and you will read on here lots of posts where ladies have gone through this and are out the other side of it.
Sending you hugs
I'm going out my mind don't know what's happening to me i cry all the time I'm moody bad tempered never been like this i was a very confident women before my beast cancer what's wrong with me