It is completely normal. Everyone will feel this way. It's inevitable given the nature of the job, having such a long commitment with time, money, and effort, and the amount of mental, emotional, and physical stress that can come with residency. What will get you through it is remembering your reasons for going into medicine, and why you picked the specialty.
There are cases where residents/interns will switch specialty because they find out they aren't happy in it. A few people leave and pursue non-clinical or even non-medical jobs. Before you go down these paths, you should make sure you know what it is that you want to be doing and where you want to be in a few years. There are dozens of these threads with similar scenarios on SDN if you do a search.
