Type 2 Diabetes Question

Ca
My question is for those of you with type 2 diabetes.   When did your doctor decide to put you on insulin?  
I've been taking Metformin for about a year now (no insulin).   However, lately my blood sugar is high although I haven't been eating differently than normal.  I know I need to speak with my doctor about it.  I'm worried that I might have to also start taking insulin.