Happened to be checking this sinusitus thread and ran into your post.
I just had the same surgery you are having this past Monday. All of my
sinuses were moderately to severely blocked and had to be cleaned out
as well as correcting a deviated septum as you are having done. After
the surgery, they taped a gauze strip under my nose to catch any blood
leakage. I replaced the gauze fairly frequently the first night. By
the next day, most of the steady leakage was over (I just kept some
kleenex handy after that). The biggest problem the first few days
after the surgery has been the feeling of the kind of severe
congestion you get with a bad cold or a sinus infection. Since the
doctor used splints instead of packing (he told me most doctors don't
use packing anymore), I was able to breath a tiny bit through my nose
so that kind of eliminated that "fear of suffocating" when you can't
get any air through your nose. Pain has been little or none. A couple
of tylenol has taken care of any discomfort. Actually, the most
discomfort has come from one of the splints that seems to be pressed
or digging into some tender flesh near the opening of one nostril. If
it wasn't for that, I would have actually experienced no after surgery
pain. I go next Tuesday to have the splints taken out and the nurse I
have talked to at his office says most people feel great improvement
in breathing after the splints come out. Aside from the congested
feeling and "balloon head" feeling, you will probably feel very tired
the first few days. That kind of exhausted feeling I had when I had
sinus infections. Also, if you want to lose some weight, this might be
a good time to do that since after 5 days food still has no taste
(since I can't smell anything I guess).    :)

A couple of suggestions: ask to have any of your post operative meds
prescribed a couple of days before surgery so you won't have to pick
them up after surgery. I have had a couple of different surgeries now
and the last thing you want to do after surgery is wait in someone's
car in the parking lot of your local CVS or Walgreens waiting for them
to get filled. I was given prescriptions for pain and antibiotics.
Only used the antibiotics so far. Also, every med site online talks
about the importance of irrigating your nasal passages after the
surgery (after the bleeeding stops). Some suggest saline nasal sprays,
some a bulb type irrigation. Mass Eye and Ear lists both. I was using
NeilMeds Sinus Rinse kit for previous sinus infections. The kit comes
with an 8oz sqeeze bottle and 50 packets of solution that you mix with
distilled water (from the bottled water section of your supermarket).
Runs about $12 at CVS. They also have a 100 refill pack for about $13.
So far it has been a life saver. The rinse cleans out most of the
"crap" that collects in there after the surgery. With each day there
has been less blood "crap" and more plain water coming back out. I
have been using it 3-4 times a day (1-3 bottles worth each rinse).
Since you can't blow you nose for several weeks, the rinse helps to
relieve the awful congestion feeling. And supposedly it keeps
everything from drying out and hardening in there which the doctor's
office will have to clean out anyway in follow-up visits. I bought the
saline nasal spray too, but doesn't seem to be as effective. If you've
never tried nasal irrigation before, try it out before the surgery. It
looks kind of gross when you do it the first couple of times but it
actually feels good after you get used to it and there is absolutely
no sense of "drowning" if you follow the directions which are pretty
simple. Anyways, that's it into day 5 so far. If I see that someone
read this, I'll let you know how the "splint removal" goes.

I wouldn't worry about the blood loss thing...appears to be minimal.
Good luck with your surgery!