too tight

The attire I wear has to be smart. However I think they'll let me off. 
Anyways, is it too soon to be feeling so big and uncomfortable in clothes?! I'm only 16 weeks 5 days and this is my first. I'm not that big either and my clothes still fit me. I wear a high waist skirt and I must admit after I eat it's hard to digest. 
Should I invest in new clothes? I was thinking maybe a black shirt and some leggings will do.