You may want to consider changing bottle size or brand of the NAC you have been ordering.
Re: XClear, I bought some, and had problems taking it, but am still gamely trying to get myself used to it, since I bought it and hate to let it go to waste. I have to take it about an hour before I need to do anything, as it takes that long for my sinuses to settle down. And that’s just with one squirt in each nostril - I think they recommend up to three? Yikes! (What was this stuff supposed to be good for again? I forget!)
I really am sorry you have problems with the XClear, like everything else, it may not be for everyone, but when you’ve shelled out hard-earned money on it....
I found out about it from my dental hygienist. By the very nature of her job, she is close to people’s mouths all day long. I think she told me she uses 2 sprays in each nostril every evening.
I only use it when I come home from the grocery store, or if I have been running a bunch of errands, I don’t use it on days I’m just home with my husband and dogs.
XClear is purported to kill covid virus in your sinuses before it replicates and gets into your lungs. (Short, unscientific explanation)