Help getting over fear, paranoia, or anxiety while trying to go to sleep in the backcountry?

Hi, im in love with backpacking and im starting to look into longer trips as i usually go out with a few buddies for 3 or 4 days. Last year i attempted a 10-day trip and the combination of my friends physical state and my mental state pulled us out. we were hiking about 25 miles a day and it was getting to him, but what got me was not being able to go to sleep ever. It didn't help that we had to deal with a mountain lion or bobcat the third night. he decided that we should just go slower and just have fun with the remaining supplies and head out afterwards, but I had become scared to stay out another night. I know any serious mountain lion encounters are unlikely (although I've had to fend them off 3 times now) but I would really like to find a way to be able to lay down and not worry about every little noise. Do you guys have any suggestions for trying to get over this? maybe a solo night? I'm planning on doing a 2-week trip this summer and hopefully the PCT in 2017 so id really like to get over it. Thanks.

TLDR: I always have a hard time going to sleep while backpacking because I'm always paranoid about every little noise, looking for solution