Similac formula

Veronica • George Alek Jr 4/08/17💙 Layla Jae 8/16/2018💜 Currently pregnant due in November
My baby is 1 month and I have him on Similac sensitive the orange powder container but I feel like it's not filling him up enough because he's not sleeping enough during the day. Should I switch to a different kind of Similac?I'm calling his doctor tomorrow but I'm worried because he's almost done with the container I have now,please help..