I am very sorry to hear that you are having dfficulty coping with stress and auxiety , due to the fothcoming final examination . I am more sympatish with your being depressed ; let me tell you however that taking a few common 'sense steps wuld restore condidence and cheerfulness in you .
I think that you are working very hard , and not taking enough time for breaks . Do you know that preparing and doing exercices endlessly produce more auxiety in you ? that is why you do not feel yu have time to spare for your friend and to enjoy some of pleasure of life you are entitled to .
So , as i said you should relax and sleep regulary , meanwhile having leaving your brin to process the hardest points of lessons and activities you ought to go out for warlks or practise sme sports everyday to help you relax . You had better not to worry constantly about the time when your exams occur .
I think that after all , you have reached a good level of competence , and that you have enough strategies at this stage to decide how to organise your work . Let me tell you again that when the exam comes start with the thing you can do easily and leave time for the most tricly parts .
I am sure that when the time comes you will be able to overcome your stress and perform quite successfully .
I wish you all the best and good luck .