Feel so much sympathy for you. DD1 was a screamer - cried non-stop and it is like torture.
Remind yourself that listening to white noise combined with sleep deprivation is what they do to torture people, so it is not your fault you feel so bad.
You have a high need baby, which when you have had one, you understand how different it is to an easy one. Thankfully you have had one good baby so you will get less worried that you are doing something wrong.
Remember it will come to an end, so you need to take it day by day, hour by hour until it is over, which will be very soon. You should get an improvement at about 6 weeks, with another at about 12 weeks so hang in there.
Some practical tips though - you may have tried all or some of these, and every baby is different, so they may or may not work for you.
Colief - we were passed on this tip by friends thank god. It is an enzyme which breaks down the lactose in either breast or bottle milk, and it was brilliant for dd1. It is expensive, about 10 pounds per bottle which with breastfeeding will last a week. You get it from Boots and it seems to make a huge difference to colicky babies who suffer from wind. Our dd cried all the time as well, all day all night, but this stuff seemed to ease it a lot. Once we ran out and it was straight back to the crying, so I would never be without it.
Someone has already mentioned reflux - worth checking with the GP.
Baby Einstein DVDs (don't be put off by the rather hothouse sounding name). To catch the babies attention for up to half an hour. Yes television is "bad" but to give you half an hour when you really need it is helpful.
All the other tips mentioned are really useful. When things got really bad I used to set off with dd1 in the pushchair and just walk. Crying sounded quieter outside for some reason.
Am thinking of you as you get through this really tough situation.