Strange period, don't know what's wrong?

So I started my period 2 days ago.Yesterday, it suddenly stopped for a few hours and then it went again. Then today, the same thing happened and no blood came out for like a few hours while I am supposed to be on my ‘heaviest’ day. Is this something that can happen, or should I worry? Also, this time before I started my period I did not have any signs that it was going to start while normally my skin gets worse and my breasts very tender etc.

Oh and I must say that I took the morning after pill about 2 weeks ago, can this have something to do with it?