My 6 month old has been sick since 2months old?

Our 6 month old has been sick since 9wks old. First we thought cold, then after 4weeks they did antibiotics. Didnt help. Then they keep saying its just her reflux. As she suffers bad reflux, which she is on Prevacid twice a day and maalox as well. We have been to the ER for RSV and stuff and negative. Has been tested for dog allergy, as we have dogs, and negative. Then they said it must be her reflux. She has been congested, congested coughing, stuffy nose, watery eyes often, sneezing but I know sneezing with babies can be normal. Are in a 2yr old home and we keep it very clean, air purifiers, dust often, vacuum 3 times a week, purifier in her room, cool mist humidifier in her room. Is it possible she has asthma, or something else, or is it really a bad case of reflux? I am calling tomorrow to be referred to an ENT, I just want to make sure we arent missing something. Its terrible seeing your child sick for so long. Just wanting some inputs from parents whom might have been in the same situation. Thank you!