Well done for hanging in there! Things will get easier as the days go on - the first week can be a complete nightmare!
There's definitely some great advice on this thread. A couple of suggestions that you could perhaps try too....
If he seems to be continuously feeding, which from your posts suggest that he does, is there any way you can try and lengthen the feed, by keeping him a little more alert for the time on each breast - perhaps tickling his feet, stripping him down a little so that he doesn't doze off quite so quickly and takes in more milk. Also, I remember from when DD was tiny, she would cry, I'd offer her the breast, she'd feed, sleep a bit, cry a bit and the cycle would repeat. Sometimes, she'd be tired or need winding, so perhaps if you think your little one has had a good feed and he starts crying minutes later, then could you try rocking him, burping him or taking him for a little walk (in a sling perhaps) so that your breasts get a break!
If your DS is gaining weight and producing wet and dirty nappies, then perhaps you might be able to try these other tactics rather than automatically feeding him every time he cries.
Anyway, well done for persevering! I remember the first week being so difficult with DD but I ended up feeding her for 2.5 yeras! I'd definitely see if you can find a breastfeeding support group in your area. Sometimes the other mothers can drive you to the group if you're still exhausted!