Wa'alaikumassalam! Aih, this is so common lah at 4 months, I had the same thing, felt macam nak pitam bila berdiri lama or dalam crowded places It's usually the combination of hormones, blood pressure changes, and baby taking up space so breathing jadi tight. A few of us tried sitting down whenever we feel dizzy, drinking lots of water, eating small frequent meals (jangan skip), and honestly, avoiding crowded kedai when we can, no shame in online shopping atau suruh hubby go! If the pening, loya and breathlessness keep happening or get worse, do check with your doctor cepat-cepat, sebab they can check your iron levels and BP to make sure everything okay.