there is one thing that can hold to key to your having complete control over your emotions that that is called releasing. Releasing is based on the premise that between stimulus and response to that stimulus ,there is a space and within that space you have a right to choose.
Too many ppl have come to accept that they "have to" respond in a certain way because its expected of us or society tells us or we are led to believe etc.
Releasing is the process of catching negative emotions within that space between stimulus and response and letting them go and therefore preventing a build up of more negative emotions.It is done by habit and is a very powerful tool in preventing ill health and unhappiness in ppls lives but because its not a hugely scientific method it is seen as too simple to follow.
Its just being aware of that space, taking a breath and just consciously letting go of that response. It works and comes with practice.
By the way ,most negative emotions come because of an attachment we have to a particular thing.
try it and see,