Reflux and dairy

So my daughter is 2months and has reflux. Starting a week ago I have completely cut out all dairy and soy to see if it helps her reflux. It takes about 3 weeks to see if it helps/worked. Tonight I accidentally ate a bowl of popcorn with butter... I totally forgot and didnt even think about the butter on it... should I restart counting the 3 weeks from today?

I'm so pissed off because it's been so hard to totally change my diet and now I feel like I wasted the entire week.