R.J.
My big trick is to go on timeout when I'm angry, and deal with NOTHING until I've calmed down. This meant when kiddo was little I'd say:
"Mommy is going on TIME OUT." Scoop kiddo up, put him safely in his crib with a baba or sippy depending on his age... and march myself outside. 5-10 minutes of peace and quiet later I'd go back inside... thank kiddo for mommy's time out and go about our lives.
I also never blamed him. Lets face it HE was the one who ________ to which I went crosseyed and wanted to bang my head against a wall (lol)... BUT
a) I'm the one who over reacted
b) It's not his fault I over reacted
c) As a toddler he isn't even capable of being responsible for himself, much less me.
So I would take total blame for any and all of my reactions to his behaviors. If I had to go on timeout, he wouldn't get punished for the behavior (when he was little), because by the time I had recovered, it was too late to have a teaching moment. Which was even more of an impetus for me to stay calm the NEXT time.
As he got older I would send him to his room and tell him we'd talk about it after *I* had had a timeout and calmed down. But toddler-wise, he was too young for delayed cause and effect. And if I hadn't delayed I would have seriously regretted my behavior. So a natural consequence of ME throwing a fit, is that I didn't get to also discipline him. Sort of like "He wants a toy, throws a fit, doesn't get it" for me equaled "I wanted to discipline my son, but threw a fit, so I didn't get to".
As time went by, timeouts taught me the same kind of self control they teach kids. Which is a good thing. Especially, if you belive as I do, that getting emotionally invested in an argument with a child is the same as getting emotionally invested in an argument with a piece of furniture.
SO THAT ASIDE....
Honey, if you're feeling like you're losing it/ losing yourself... seek help. It may be a chemical imbalance, it may be hormones that could be fixed, it may be depression, it may be 1 of 100 things. You deserve to feel like yourself. And if it's more than just needing to "practice your patience" (like me), why tie yourself up in knots when there is an "easy" fix? AKA, see a doctor, have tests run, get dx'd, get better.