You should not snort raw garlic into your nose and sinus passages. Raw garlic not only gives the 'sensation of burning', it actually burns the tissue.
I do not recommend sniffing straight 'cayenne powder' (although there's a few reports on the forum of people doing it). The best herbal combo is the Herbal Snuff, but you likely don't have any of that 'on hand'.
It seemed to me like hydrogen peroxide might work, so I Googled it...wallah! I don't have time to search through the links, but I see a LOT of positive reports and various methods. Check 'em out!
Whenever the body is compromised, it's common for pathogens to be able to 'take hold'. It's my opinion that what you've reported in the last few days wouldn't be caused by a sinus infection. It's far more likely (to me) that the 10 grams of glutamine compromised and weakened your body.
'Hope the H202 works for you (and that you get some sleep!).