It seems simply coincidence of timings. However, if some
stomach infection has been contracted, that's temporarily troubling and will go.
I am happy that you took extra care of eating, water etc during your stay. So no worries.
To my own patients, I suggest to take the following to correct the issues of dairy allergy:
1. BAEL ( or BILV) pulp powder + Dried ginger powder + Isabgul husk ground in the ratio of 1:1:1 and take three times a day. In the morning and afternoon 1 tsp with buttermilk or yogurt. Mix well and eat it. At night may gulp 1 tsp with warm water. No side effects. If some irritation in gastric region occurs, simply reduce ratio of ginger powder or say, increase other two in the combo.
2. KUTAJGHAN vati 2 bd with warm water.
Start taking these for a week or so. May take for longer durations. No interaction. Even your relatives having
lactose intolerance may have it too. Drink warm water ( boiled, cooled).
Now how to get. In India its commonly available. Elsewhere make efforts to find these on net. Combos will not be available. May get separately and mix yourself. Ginger powder is found , may be in your kitchen too. That may be used. Isabgul husk may be found. Grind yourself.
Hope it helps you too like it worked for thousands of my patients. I will most happy seei g happiness on your face.