Im a bad mama!

I can see that sometimes i lose my temper w my babies, toddler, and 6mth old. Id kind of get rough w them, yell at them, then feel so horrible and guilty afterwards. I still feel horrible. Im trying to be patient w them, but i cant control my temper at all, i find this happening all the time whenever my period is coming. I hate it to the max! Is there any way for me to get help?