Above Ear and Nape hair loss???

[Jasari]

Quick question to anyone with experience on this issue:

For years I had been using brand name Propecia with good results - but due to circumstance I had to change to generic brand in July of 14'.

From that point through to Jan 15' I shed badly. Like half my entire head of hair bad. Subsequently I've gotten back onto Brand Name Propecia.

The shedding has slowed somewhat but I've noticed I can still pull out handfuls of around 5-10 hairs easily from near my ears and nape every single time.

My questions is this: I've only every experienced thinning as far as a Norwood 4a pattern. It hasn't progressed anywhere near a 5 in terms of MPB - In this regard is thinning in these area's normal? From what I understand this area for hair loss is more commonly associated with stress?

Would a blood test be beneficial?