You are 100,000,000% not a) a failure, or b) a let down... you have a life! We all have lives and this is what happens and then we come back, and get ourselves back in check again. Which is exactly what you'll do whenever you're ready.
You are a beautiful woman inside and out and your weight is just one teeny, tiny little element that makes up how amazing you are.
What a weekend though! That hen do sounds UNREAL! I bet you can't wait for the wedding now!! xx