I am in recovery from stage 3 breast cancer (HER 2 positive)..

 I have just had a genetic counselling appointment on Fri! and I think I'm in total shock. It's been two years since my treatment finished and I was sort of beginning to get back on track. I filled in a genetics form probably 18 months ago, then out of the blue I get an appointment. It turns out that because of  the type of Cancer I had and family history that I could have an extremely rare syndrome Li-fraumeni which would put me at high risk, if the test was positive of developing further cancers. This puts me in a difficult situation, should I have the test or not.. I  have three sons who this would also implicate,  if god forbid it came back positive. Does anyone have any insight into this, or advice?