I agree with wiretwister. "Normal" is fairly meaningless. Different people have different states that they would consider normal. If you're going through hard things in life, it's normal to feel a bit down. If you're watching the birth of your first child, elation is normal.

I think it's easier to think about it in terms of "rational" or "irrational". Meaning that there is a reason for you to feel as up or as down as you do. If your feelings are a rational reaction to your circumstances, given your unique personality, then you could be considered normal.

Does that make sense?