Not sure if newborns poo is normal

[thunderonlyhappenswhenits]

She is 18 days old and the last few days she's only having a poo once a day and really struggles to get it out, when it does come out it's runny and bright yellow and stinks, it smells quite acidic.
I'm combi feeding, mainly formula, she has a bottle a day of breast milk usually.

Does this poo sound normal? I'm just worried as it's become runny, not seedy or grainy anymore but quite smooth. Don't know if it's diarreah? And she doesn't seem to be going often enough

Sorry, yes I did get into the gp, she wasn't concerned about her belly or the un-settledness, she had a good feel of her belly etc and said all feels normal, I did leave feeling more reassured.

One thing we've started doing now instead of shaking the formula is swirling it around the bottle instead, and she does seem more settled ! It can't be good all them tiny bubbles created from shaking the bottles to mix the formula