I had the flu or bronchitis and now developed serious sinus infection?

Hello I am a 45 year old female with no disease and I am on no medication and very healthy. Last month I had the flu or bronchitis badly, the head pain was unbearable, it tooks a couple of weeks to get over and I still have headaches a little bit. My entire life I have always had sinus infections and my nose is always blocked. Three days ago I used a netti pot and I did it with my own salt and it burned. That night my vision was off and now for the past two days I have had double vision badly and today a headache- i have no health insurance and I literally have no money- at all- nothing for a dr…is this from the netti pot did I gives my self a sinus infection.I cannot go to the ER and be in debt thousands to find out its a sinus infection thank you.