Confusing emotions?

Last week I had a week from hell. Everything that possibly could go wrong seemed too. And it wasn't just minor things, stuff happened that could've seriously fucked my life up. It was hard and emotional but near the end of the week I got most of it more or less straight end out. It was hard but when it was over I found myself happy and able to smile.

This week has been great. Not only has nothing particularly bad happened, quite the opposite I've had numerous good things happen to me this week. In fact I'd say this has been one of the best weeks I've had in months. But despite this week being so great, I've felt strange, off, and even somewhat depressed.

I don't get it, I came out of the week from hell with a smile on my face but this week that's been great I've felt depressed and not like myself.

is it normal I've felt this way?