It's doubtful smoking anything will give you a sinus infection, but you do sound like you might have one. I don't smoke anything, but I get the occasional sinus infection because of allergies. On the other hand, smoking too much of anything is a pollutant, as it doesn't burn completely. Just like the exhaust from your car. Everything in moderation, and a water pipe is much safer than joints, since you're not burning paper, and eating it is safer still. And remember, as you age, things catch up to you. That's why most of us cut down drastically or stopped completely in our twenties. Sinus infections most often got away on their own, and there are herbs you can use if you want to avoid antibiotics, but you do need to see a doc to get a diagnosis, and if it's virulent, you will need antibiotics.
Yes, you probably have an infection. However, smoking ganja would produce the same symptoms as smoking tobacco, that is congestion and chronic bronchitis and sometimes clogged sinuses.
Yes, see your doctor. Sounds like you've got a sinus infection. Smoking weed can do that.
Feel better.