An addiction is a mind disorder characterised by an overwhelming compulsive engagement in rewarding stimuli despite adverse consequences... In laymen terms, it's an act, a behaviour that, even when detrimental to our life, we are compelled to indulge.
This could be in the form of drinking alcohol in excess, gambling, shopping, eating, taking drugs (including prescription drugs), pornography, sex and exercise. The list goes on! They can all start small, usually unnoticed by yourself or others, this act may have played a part in making you feel good, taking your mind off something that was making you feel bad, call it escapism.
That's ok but when you find yourself acting in this way when there is no need for it, then that craving has a hold of you and that's where I step in......