I had a cold, (maybe a flu) and I was treated with amoxicilyn pills. After that I'm having sinus infection with high density secretion (color - yellow /green) for almost 15 days now. I don't have headaches. I have a lot of trouble breathing. I've tried inhalation with sea salt in boiling water but it doesn't help. Please advise me what to do

Neither a cold nor the flu, both of which are viruses, can respond to antibiotics, which are for bacterial infections. Doctors hand out antibiotics much too soon and much too often. More and more people and viruses are resistant to the usual antibiotics like Amoxicyllin, so they need more rare and expensive ones, IF they really do have a bacterial infection. A cold, flu, or bronchitis can turn bacterial after some weeks. Generally you should wait for a virus to run it's course, a minimum of two weeks, before you take antibiotics. You stay warm, rested, and drink tons and tons of weak fluids (broth, water, watered down juices). Good old chicken soup, because onions are good too. Gargling with salt water is good, as often as possible. No need to pay extra for sea salt! There are salt nasal sprays too, in drugstores.

There is controversy about the use of antibiotics, so you don't need to take my opinion.

Neither a cold nor the flu, both of which are viruses, can respond to antibiotics, which are for bacterial infections. Doctors hand out antibiotics much too soon and much too often. More and more people and viruses are resistant to the usual antibiotics like Amoxicyllin, so they need more rare and expensive ones, IF they really do have a bacterial infection. A cold, flu, or bronchitis can turn bacterial after some weeks. Generally you should wait for a virus to run it's course, a minimum of two weeks, before you take antibiotics. You stay warm, rested, and drink tons and tons of weak fluids (broth, water, watered down juices). Good old chicken soup, because onions are good too. Gargling with salt water is good, as often as possible. No need to pay extra for sea salt! There are salt nasal sprays too, in drugstores.

There is controversy about the use of antibiotics, so you don't need to take my opinion.

It was a bit strange for me too when she gave me the prescriptions. I'm no expert but I know that flu is a virus and antibiotics anti bacterial medications. That's why I don't want to go to see her again. I'm drinking a lot of fluids especially tea with honey. I will mak some chicken soup as well. But why gargling? Isn't that for sore throat? Thanks a lot for the advise anyway

Gargling is good for any phlegmy symptom. It helps clear out phlegm that is clogging the sinuses, back of the throat, even eustacian tubes. It helps stop it from being a breeding ground for bacteria.