Welcome to the forum, great to have you here!
So when making a change to your diet your body can react in different ways. There was a really handy article we built out all about bloating which might be able to help hopefully narrow down what the cause might be - Bloating 101: What Causes Bloating? | Huel US
We had a thread here which goes into bloating and some people shared their experiences - Need advice on stomach pains and bloating - #2 by Talort
Also take it easy. If it doesn’t go away, drop us an email at team@huel.com and we’ll be happy to look into this for you and see what could possibly causing this.