Can only echo what the others have said. I remember when alex was 10 days old he spent almost 3 days just constantly feeding I remember thinking god I can't do this but it did eventually calm down. They go through growth spurts (didn't have a clue about these in the beginning) if you Google them you can get a rough idea of when they are due I think it's something like 10 days, 3 weeks, 6 weeks etc ... you know when they strike as they eat non stop day and night but when they are over you do notice small changes in your baby, clorhes a bit smaller, start smiling, grabbing things etc .. so when your up at 3 .. 4 .. 5am just think when it's over your baby will have learnt a new skill.
Just ride it through hun, as annoying as I found this when everyone said it to me it really does get easier I promise. As soon as alex hit 8 weeks he was like a different baby, sleeping more, eating less ... and now at 20 weeks its a breeze.
Message me if you need any advice or just wanna blow off steam xxx