It’s actually quite normal, especially since baby’s on formula milk. As long as baby’s not in discomfort and is feeding well/active, you can continue to observe:) if it extends past 7-10 days, then you might want to check in with a doctor
My baby was on mixed feed and the record was 6 days.. We asked pd and pd said its fine.
BTW try to burp your baby after every feed of jot gas in the tummy can be very uncomfortable for them. You can burp a sleeping baby too