Several things happen to me:

-I see only tits and asses (on women only, lol)
-I go a little mental, as my physical need is tied up with emotional needs.
-I get angry with my SO, as she doesn't attempt to really satisfy my needs (hence my participation in the hobby)
-Jacking off doesn't work to calm me down, only real pussy does it for me.
-I can't concentrate and end up wasting a ton of time cruising TER and escort web sites, viewing online porn, etc.

Second related question:  How long is too long?

For me, it starts slowly at about 2-3 days, gets worse at a week, and at two weeks, I go nuts.

I'm using the royal "You", not you personally. And I'm referring to the practice of celibacy amongst Catholic priests. Which it seems, some need much more practice.

Sick jokes aside, I experience the same things you do although longer time spans since I'm getting older. The last point you mention doesn't ever seem to go away no matter what.

your first point.

Two days is too long. I'm sure to get slower in my forthcoming old age.

Your eyes roll back into your head, the left side of your face becomes numb, your lips turn blue and your nuts fall off. Oh wait, that's what happens from too much ouzo!!

pass the OUZO down here. Don't tell my GF. She hates when i get MP'ed.lol

with my hands down my pants on my crotch.  I'm not popular at Safeway and Home Depot.

6 months.  I have not sex.  I almost forgot how to fuck.

tolerance and patience.

If I go too long without getting lucky I can get punchy, become intolerant of apparent idiocy and impatient with people who demand more than they produce.

after a while, those months between sex seem to just fly by!  Soon you will be marking it off by years instead of months.  If you're lucky, you will stumble on to TER, and the only think keeping you from having great sex whenever you want it will be the depth of your pockets!

For those of you who are going crazy after 2-3 days, get a freaking hobby!  I love sex as much as the next person, but I'm not about to place my cock in a shop-vac cuz I haven't had any for a couple days! Some boys just never grow up!

Yes, you see bodies everywhere.  You desire that feeling of skin touching skin.  And the companionship that accompanies it.  For a while.  

then you get irritable.  Perhaps angry at the world.  Jealous of the guys who have more than they can ever appreciate.  For not quite as long as the previous stage.  

The news is that after long enough, your balls just quit trying.  Keep the exercising up high enough and  you don't even get morning wood anymore.  

But boy, you can get sooo much more done!