Darling, your GP has done exactly the right thing - honestly, she is referring you to rule out anything sinister and to find out exactly what is going on. IT DOES NOT MEAN SHE THINKS YOU HAVE BREAST CANCER. There are all kinds of breast conditions connected with hormones so the clinic will be able to tell you just what's what.
Having said that, if it is BC, please remember that diagnosis, treatment and aftercare have come on in leaps and bounds over the last 25 years, and you will get the most superb care from the NHS. I'm 64, diagnosed in 2010, and I know my treatment - all successful - has been so so different from what my mother's generation had to endure.
You will get excellent advice and support from this site, and the Helpline staff are great, they are so knowledgable and comforting.
One last thing - whoever goes with you to appts needs to write everything down, so you can think it through back at home (or do it yourself in the waiting room after your appt if you are on your own) then anything you don't understand, ring the clinic and speak to your breast nurse. They are used to us not taking it all in at once and THERE IS NO SUCH THING AS A STUPID QUESTION.
You will get your appt within 2 weeks of your GP referring you, and whatever is wrong with your boobs can't get any worse in that time - the waiting is grim but you'll get there.
DONT Google, just use this site and MacMillan cos there is some crazy innaccurate and downright scaremongering stuff out there and it's all WRONG.
all the very best
grumpy