How to overcome anxiety? Watch
You should go to a doctor regarding your anxiety.
It’s not as straight forward as just putting a smile on your face (although there is plenty of evidence to suggest forcing a smile on your face does improve your mood), but it is also the case that doing nothing is unlikely to improve your situation. If you seek help (and you should, as should anyone, even with mild anxiety) you’ll be given the appropriate training and tools to manage (and perhaps even overcome) your anxiety...
In the interim you might like to talk to your family or loved ones more openly about your mental health (don’t buy into the stigma), try not to avoid the things that cause it to be triggered (avoidance is the enemy), and research and practice something called “mindfulness”.