Mood swings are the worst . It is like riding a roller coaster going up and down on slides all of a sudden from one second to the other. One minute you are angry about something really minor and the next you can just have forgotten about it and be normal and the next minute you can be sad about something that you saw or something that came up to your mind. All of these changes in the mood make you feel  like being a crazy person cause these rate of changes is unhealthy for the mind. It is also tiring for the mind to be in such a situation because it can not find the proper peace that it deserves. It can be worked out with some ways like cognitive behavioral psychology or drugs it is up to you how you want to fix it. Thing is that surviving these roller coaster changes you learn to control yourself better and react to situations better over the years and the experience you have.