If you find that it doesn't go away and you just can't feel happy anymore, please be aware that clinical depression does exist, where it's not your fault and you don't need to suffer through it alone. Clinical depression is a brain disorder where you are, quite literally, for some reason, incapable of releasing neurotransmitters that make you happy.
From your story, I am assuming you don't typically feel depressed, so I hope things work out for you. It may take some time, but, once you are able to move on, things should start reverting to normal.
However, if your mental state does not improve with time, I strongly urge you to speak to your parents, your friends, or a counselor about it. The people around you are there to help you, so if you do have a problem outside of your control, know that clinical depression can be treated, just as long as give yourself the opportunity to be helped.