It may or it may not be something wrong with you. Interests change as we change. Is there something new you are interested in? Maybe it is just time for you to stop playing games or choose completely new types of books? You need to ask yourself what you really want. You may find the answer. If there is no answer that you might have a problem. They say it is one of the signs on depression but it is not always so. I was always a very social person but at some point of my life I started liking being alone. I would decline party invitations, stopped calling my friends as often as I used to, and preferred working out at home other than at a gym as I used to. I was really worried about such changes. I went to a professional and was diagnosed with depression, put on drugs, and I started a therapy. I didn't feel any changes so I stopped. Now, several years later, I understand that I just changed. I wasn't depressed. I just became different. I didn't like my old interests anymore. I became less social but apparently it was time for me to spend more time with myself other than with other people. I stopped reading but I started writing. Changes are not always bad. However, if you feel like you don't want anything at all, you need a professional help.