1 week old hasn’t pooped!

Kami

So my LO makes a week old on Friday and hasn’t pooped since Tuesday night! she’s formula fed and I give her Similac sensitive. Should I be concerned? I called her doctor and she recommended that I try using a q-tip and inserting it into her rectum to get her to poop! Has anyone tried this and it worked? Any suggestions? now her belly isn’t hard and she isn’t fussy or anything just a concerned mom is all