How can I forget my dear ones to commit suicide?

I am a 19 years old boy and wished to study Physics from my childhood.But unfortunately,I got unexpected marks in mathematics which was nothing but wrong and now I am unable to get admission to any good college despite securing 94%in Physics.The number of seats in those colleges is so little that I have no hope to get admission in them.Also I loved a sweet lady who left me making me alone.I wanted to commit suicide much more times ago when she left me,but I couldn't.But now I have no intention to live.Please tell me how can I forget everything in this world which impede to do this but please don't encourage me to live.