Congratulations on the new job!
Stress affects us like many other diseases, sometimes more. A new job, selling the house and moving, a baby on the way... Any one of these is a major stresser.
Engineering minds are used to problem solving. The mind is used to having the answers for an entire project up front. Life sure isn't as easy nor linear, so it doesn't fit into the compartmentalize engineering mind sometimes. Don't worry, everything will fall into place as time rolls along.
“A journey of a thousand miles begins with one small step”