Other moms PLEASE help?

My one month old has what i think may be colic except instead of curling her legs up, she sticks them straight out and tenses up while crying/screaming inconsolably, the only thing that makes her stop crying is when my husband holds her arms length away from him and swings her up and down - thats literally the ONLY thing. ANYONE have ANY suggestion whatsoever? by the way she eats soy formula, so its not lactose she has reflux but its treated with 2 medications soi its not that she just keeps her legs tensed and straight out like that constantly please help