...
facepalm.gif
Ahem.
OK, with that out of the way, you should know that it is actually pretty difficult for that irrigant to get into your sinuses unless you have had sinus surgery. It mostly gets washed through the lower half of your nasal cavity. It is going to feel funky for a while in there but it isn't the end of the world. Peroxide kills tissue. Dilute peroxide is used for wound cleansing (and even then, only for removing already dead crap) ... but your nose is not a wound.
What you want to do now is to keep irrigating daily with some isotonic saline solution, not plain water, because that also kills tissue (especially tissue which has already been messed up by having a peroxide bath). The recipe posted by PARover above is a good one. This is all that is needed for most cases and in most people. I will sometimes have people put compounded medications in there to treat certain conditions, but for the average user, the saline solution is all you need. I would also recommend getting one of the neilmed electric irrigators called the "Sinugator." You can find these at Target or Walgreens (or online at neilmed.com) for about $25, and they are worth the expense.