My 2 Year Old Has Been Saying She Has An

My 2 year old has been saying she has an owie tummy off and on for a couple weeks. Last week she had a 24 hour flu bug and I didn't give her milk for 3 days. She has been waking up in the middle of the night crying and her appetite is really not there. She loves milk but I wonder if she could have lactose intolerance? Plus after being sick last week her gag reflex is hyper-active and she gags or throws up her food a lot.....