Worrying a problem in circles

I've been told that I worry a problem in circles. My Granny would've said, "I borrow trouble."  I was reading the other day and I came to a part in the story between two characters where the topic was worrying a problem in circles. The main point was that worrying a problem in circles only brought on more worries and made the character stressed and tired.  The guy character told his girlfriend to "worry a problem in a straight line", or as my Granny would've said, "Don't borrow trouble."

Like the character in the book, I find it difficult to do. I am often faced with a problem or worry and immediately begin to think of all of the bad things that can happen as a result, instead of looking at it like it is.  Jason was very good at steering me onto the straight and narrow path, and sometimes I feel his presence today.  For example, I had a doctor's appointment today and got some news I wasn't expecting.  The kids were with me so the brave face immediately came up, but inside I was racking my brain trying to think of soothing things to say to the kids so they wouldn't worry.  Once I was alone though, I got caught in the Worry Circle.  Thinking of all the things I would have to do to take care of things got overwhelming.  At the point where i got so overwhelmed I wanted to cry, I a thought popped into my head, "Call Kevin. Talk about it."  That's Jason's way of telling me, "Worry in a straight line.", and my Granny's way of saying, "Don't borrow trouble."  It helped to talk and focus in on the next step and not all the other steps that could possible occur based on different scenarios.  But it's still difficult.

The best suggestion from the characters in the book was to trust in God and find comfort in the Bible.  So I got to wondering, what verses in the Bible encourage the believer to find solace in God. Any suggestions?