Hi there Kimomolo ,
Are you having any therapy.....counselling or CBT? As this could really help to control your anxiety.
There are some great online CBT sites
Have you tried focused breathing , that might help ease your sniffing. Think about the sound of your breath as you breathe in and out. Then focus on the movement of your breathing and start to deepen the breath slowly and evenly. It might help to count in your mind.....breathe in for 3 , hold for 3 , breathe out for 3 - counting helps to distract your mind from whatever is causing the anxiety.
I hope I have helped in some way.
Take care ,
swallowing is common from anxiety and mentioned here often
for the sniffing, try squeezing your hand instead