morning sickness & depressed

Ashlee
So I'm 5 weeks and 6 days today, my morning sickness has well and truely set in, feeling nauseous allllll day!! & I know it's only going to get worse! 
I've all of a sudden been feeling depressed and thinking to myself why am I doing this again?? Am I sure I want this baby?? 
This is my 4th baby & I never had this with the other 3. 
Anybody else get like this? Is it normal? Someone help please