It does sound like you are worried about your situation. Obsessions can have a few different causes, depending on your symptoms.
One, you can have Obsessive compulsive disorder. Obsessions, which is what you are coping with, occur when you are so focused on a topic or topics that it begins to interfere with your ability to live a normal life. The obsessions often create such anxiety that you develop a compulsion to try to rid yourself of the obsession. Frequent handwashing is an example of a compulsion.
Two, you could have an anxiety based issue. People who have anxiety become so worried about feeling out of control that they become obsessed with certain thoughts. In your situation, thinking and talking about energy efficiency has become a way for you to try to deal with your anxiety.
Three, obsessions can occur when you are trying to block out disturbing thoughts. If you repeatedly worry about something, it can prevent you from thinking about what is really bothering you. This usually occurs when you are exposed to some type of trauma, such as childhood abuse or a traumatic event of some kind.
The best way to understand the source of your obsessive thoughts and find a way to treat them is to get a full evaluation by a therapist. They can ask you about symptoms and match them to a diagnosis. You are then offered treatment that would best fit your needs and help you resolve your issue. To find a therapist, ask your doctor for a referral. Or you can search on line at http://therapists.psychologytoday.com/rms/.
I hope this has helped you,