You are the average of the 5 people you spend the most time with. So who are talking to on a regular basis and what conversations are you having? If more than 50% of your conversations are negative or are spent discussing nothing productive - it may be time to make a change.
You will need to change the topics of your conversations OR you may need to find a new circle of people to discuss new and different things with (or may need to do both).
Change is good.... embrace it with open arms. While it may cause you to feel uncomfortable for a little while - what is on the other side will be amazing.