awww, mama. This time of childhood is really all about survival. Be gentle on yourself. It gets easier and easier, it really does. It sounds like you're doing the best you can, and you're probably doing it on not nearly enough sleep!
Its hard to figure out the right thing to say and do under those conditions. For me, the best I could do was to hold myself still and keep myself from saying something I would regret. Never mind trying to model how to express anger appropriately... I just wanted to not express it inappropriately!
Hang in there. Chant to yourself "this will pass this will pass this will pass." Give yourself treats, go easy on yourself, do your best to get some breaks if you can.