I'm sure you can feel depressed if it was something that was a big part of your day that you enjoyed. My son went to China and could not take his video games with him, and he said he felt *lost* for a long time without playing them.
Could be! I know people who grew up playing video games nearly all day when they were home and it really affected them. Some people don't do well with too much gaming. Some people get upset and aggressive more easily and their moods change. Of course this doesn't happen to ALL gamers, but there's a chance. If it was a big hobby of yours and you gave it up, sure that can cause some changes in your mood too.