Negative thinking is definitely a contributor to anxiety, IMO. It can always make anything worse. I'm used to thinking negatively about things, too. If I do not change how I am thinking about something, my anxiety, depression, etc. will get worse for sure.

Try using self-soothing techniques along with positive thinking. As soon as you are thinking negatively about something challenge it with a positive thought.

Example:

Thought: I can't handle this.
Challenge: I can handle this.