Self calming suggestions?

Hi,

Im currently studying at uni and im really struggiling  im practically in tears every day or on the verge of tears. 

Im very slow in understanding what i need to do, it taies me ages to understand or i never do. And then in my free time i just want to shut away doing what i lioe then focus on uni. 

I struggle alor with maths and physics, even just hearing a mathmaticl term puts me in fear mode and i completly shut off. This is affecting some of my modules and exams where its maths based as im not listining in lectures as im shutting off wihout realising and when it comes to exams i completely self destruct and i cant do anything.

Is there anything i can do to help relax me before exams etc to stop me from going to fear response and shutting off?