Its probaly because she realizes that she's gettin older and so is her 'baby boy'. My dads g/f used to be just fine 8 years ago or so. When she hit 50 3 years ago she's changed. If you say happy b-day to her she'll say Fuck you. Or say how she hasnt done all this shit that she hasnt done. Or her work will get her all pissy.

Its probaly just gettin old. Mid-Life crisis mayby? Hell my dad got a tattoo after swearin they we will never get one. Or himself for that matter.