Lobular Breast Cancer Diagnosis in 40s

I feel utterly distraught. Have been diagnosed with Grade 2 Lobular Breast Cancer. Am terrified and feel all joy has gone from the world particularly as this cancer can (not will) have late recurrence in the future - eight, ten, twelve years into the future. This uncertainty does not suit my personality - I will obsess over it.

My daughter is only 4 and I am terrified of leaving her motherless. 

Next steps: MRI (they think it’s 3.5cm); then either chemo and mastectomy or vice versa - maybe radiotherapy and hormone therapy.

Sorry to be so negative - found out last Thursday.