How to deal with stress, anxiety till prelims.

Realising that life is "Dukkha" and happiness is momentary 

Breathe through it. A lot of times this stress manifests physically in the body. Eg ringing in the ears or palpitations or shortness of breath or fidgeting or simply shaking of the legs. In most cases, just breathing through it helps. Breathe in - Hold for 5 seconds - breathe out very slowly. Repeat this atleast 5 times. Hope it helps. :)