If it has anything to do with feelings like happiness or anger, then consider it emotional. A co-worker who cries at the drop of a hat is overly emotional.
If someone says "Stop being so emotional!" they're telling you to calm down because your feelings are out of control. When you're emotional, you're feeling lots of feelings, or emotions: happy, sad, afraid, lonely, mad. An emotional speech makes you stand up and cheer. An emotional movie tugs on your heartstrings. The opposite of emotional is logical: logical things have more to do with your head, while emotional things are all about your heart.