Mixed feeding, no poop; Day 2

Decided to begin giving my 7-weeks babygirl FM (Similac) at night so she can sleep longer and also to get used to FM before starting infant care. Gave 60ml on Wednesday night, pooped a whole lot the next morning but that’s the only time she pooped. Hasn’t pooped anymore since. Is this a concern to bring her to the PD? I have stopped giving FM for now cause worried that she might be constipated, but she seems fine. Still farts and accepts BM as usual. Applied Yu Yee too but still not pooping. Advice please, mummies!