I'm not writing this at a low point so it's not just a pity party on my behalf.
I've got a nearly three year old and a baby who just turned one. I seem to shout/snap/lose my temper at the two year old every day.
Its becoming more and more apparent that I just don't have the patience for this parenting thing. She does things that, rationally, I know are totally normal for a toddler but quite often I just don't have the patience to discuss it with her normally and rationally. This morning we went shopping, just the two of us and she kept wandering off and I just kept snapping at her and guiding her towards me and away from other people. I know it's normal for them to be in a world of their own and not pay attention but it just seemed to piss me off more than I'd expect to be normal. 
I'm also not handling the 'never shuts up' part well. She never stops talking and generally interrupts me in the middle of a sentence to ask why, before I've even had a chance to explain. Then I explain. And she asks why again.
I genuinely don't know if all parents just this frustrated or if it's just me. It's a vicious circle because it makes me angry that I get angry and that just erodes my confidence.
Any help or suggestions? I don't want to be a mum who's constantly raising her voice or losing her temper. 