When to buy maternity clothes?

Me
When did you start buying maternity clothes? I am 7 weeks and am wondering if I should start buying a few things in a week or so and then more once I make the 12 week mark. My issue is that my tummy is always bloated anyhow - and people thought that I was pregnant - even when I wasn't. So I am not sure how soon I will be showing. When did you start showing? 
I had 3 losses always around 5 weeks - so I am really confused. Thank you, ladies. 💜