I am sure everyone pace this situation in their life, no matter how happy your are but at least you will face this sadness ones that is humans please!!! But, don't dissolve in sadness because you have a lot of shine bright in front of you, there is a lot of happiness. so.. please stop sad and face all the problem because there is good people around you and of course there is God. Don't try to avoid sadness but acknowledge it and learn to move beyond it.
Here is some tips how to deal with your sadness:
Face it the sadness --> For sure you will face this sadness so face it, thinks well and never avoid the feeling
Write to your blog or diary --> What ever you face please write it, can be in your blog or your diary, write everything you can and never think about what people thought about it because you just need to through out that sad feeling.
Talk to a friend --> Don't feel the sadness alone, share with someone you trust and that will help you to heal from that feeling.
Spend time alone --> Sometimes to spend time alone is a good way to heal your sadness, you can cry loud, you can talk yourself and think well.
Listen to music --> If you like music so you can listen music, look for the most music you like the listen and feel it to make you more relax.
Play games --> If you are a gamer so this will help you to forget your sadness, you can play all day till your sadness go away.
This some tips from me and I hope you can take it in positive way
Love you
Zatin