Anxiety is not just an emotion. From more mild forms to social anxiety disorder and unjustified phobias, anxiety may bring a lot of problems for the person who experiences it. The person feels fear and unsafe, can’t respond calmly and rationally to the situations of social interaction, changes of the environment, and even those everyday challenges which in fact are quite habitual. Understanding of the fact that all the fears and suspicions aren’t reasonable often makes the person feel blame for incapacity to control their own condition so the anxiety increases and the person just goes around in circles. Such disorders typically affect the social and professional life, so it’s no sense to ignore them! 
It may be a good idea to recourse to cognitive-behavioral therapy, but nevertheless, good anti-anxiety drugs will be helpful, speeding up the process of recovery and eliminating such symptoms as fast pulse, trembling, fatigue, and weakness.