Advice please !

Janette

Recently my babygirl hasn’t been pooping. Should I be worried? I changed formulas from enfamil to similac because she’s been throwing up too much, and similac hasn’t making her tummy upset or anything, and I give her breast milk in the am and formula in the pm, but if I don’t have enough breast milk to pump, then I use formula bc I lack of breast milk which is very upsetting. any advice?