Already showing?

So I can’t even button up my pants and I am only 4 weeks! Got a positive at 3 weeks 5 days! This is my second pregnancy but I have never had symptoms this early let alone showing! I don’t think I’m farther along but I am wondering about twins! Is this fairly normal like maybe a crazy amount of bloating or should I prepare for multiples?! I didn’t show with my first until I was 16 weeks.

Also I don’t have a scan until I’m 9 weeks! It’s killing me!