I understand your concerns. Definitely, all the symptoms you described are pointing towards depression. Moreover, you are also under severe stress because of the preparation for the competitive examination. The stress will further worsen depression and depression, in turn, makes you feel more stressed. This becomes a vicious cycle.
Moreover, depression results in poor concentration, poor memory and ultimately poor performance in the exams.
You need professional help.
Please don't shy away.
Next Steps
please consult a Psychiatrist ASAP for detailed evaluation and comprehensive treatment.
Health Tips
discuss your concerns with your family and friends and take their support, if possible.
otherwise, atleast consult on your own, but don't neglect the early symptoms of depression as they become more problematic when they are left untreated.