low mood

I am in a low mood now because of a call. So ridiculous! Why am i so easily affected by the environment, why don't i hold myself all the time? i don't know from when somebody and something start to control my mood. when i am very glad in the phone, i will keep a high sprite all the day and treat every one very kind. if the case is not like this, i will lose my temper . with the gaining of somebody's confidence, i become more and more sad. i hate this. leave all aside and choose another way. this is the only way for me to choose. Come on!