Ok so there are many things you will not be told about having a baby (I guess if you did you might reconsider lol) and I am amazed at how much 'it is normal' is used.
So far here is a few things we were worried about and have been told its normal
1) baby only cries when hungry and only one cry
2) baby has fed every 30 mins for 12 hours (cluster feeding)
3) baby wont settle after feeding (needs burping or has trapped gas)
4) baby has not slept more than 20 minute stretches in 48 hours
5) baby brings back up an obscene amount of milk after every feed
6) baby suddenly appearing purple due to purple cross patterns all over their body as shown in the picture (mottling) which is due to the fact babies develop their circulatory system over time and until then mottling can occur
Note the above are incidents which we rang the ward or we went to our gp, these did not occur constantly and at the same time. My advice here is to ring the ward or visit your gp if your worried at all, but don't be surprised if its all normal