Devastated :( Just diagnosed with SBC with lung and bone mets,need help :(

Hi ladies! Actually I am really sorry to write this post but also happy to find a community of us here.
I had my primary breast cancer in 2006.It was stage 2 and no mets or lymph node involvement.I was cured with radical mastechtomy,chemo and radiotherapy.Everything was well.At first I had controls per 3 months,then 6 months and last five years they were per a year.Everything was well.
In September 2015 my tests showed elevation of CEA.My onc immediately arrange a PET/CT scan for me.The results were clear.Than I kept being tested for my tumor markers every month.3 months later CEA was still elevating.My onc wanted another PET/CT scan and nothing had been found too.
Because my son was a 4th grade medical student at university,he wanted to check my tumor markers periodically.During this period with my onc’s advice, I had 2 colonoscopies,1 endoscopy,1 complete CT and 1 pelvic MRI.NOTHİNG,nothing was there.Because my son was too worried about situation we never gave up checking my body.But this time period was a really challenging and destructive for all of us’ psychologies.Even my onc started to think there is nothing malignant in my body since I had ‘zero’ symptoms.We decided to having TM tests for every 3-4 months not for every.
Finally at the beginning of this June(2017) my CEA level was extremely elevated with a moderately elevation of CA-125.(I just have a back pain for 3 weeks) I immediately had a PET/CT and that was it.I had bright spots in my thoracal lymph nodes,my lung(lots of milimetrical nodules),and my spine(especially L4-L5).And also there is a minimal pleural effusion in my left lung.I had a chest biopsy and the result was Secondary breast cancer.
According to pathology results my tumors situation was:
Estrogen reseptors:%100 (+)
Progesterone reseptors:/20 (+)
Proliferation index:%30(my onc told me this shows my tumor is not an aggresive one)

I am waiting for HER2 results before my treatment.
I just feel myself awful.I feel it is in every site of my body and I feel like it is late for me to recover.I have a daughter of 14 and a son of 23 who is a 6th grade medical student.
I am afraid ladies,afraid of leaving my children alone :((