Confusing about sex. Bad for all that.

Around 10 months ago , my life was normal but suddenly I feel life I have some sexual problems. I am a shy person. I try sometimes to talk to my friend , my parents but couldn't. I ignore my problem thinking that it is my illusion. During that time my big brother was unmarried at the age of 31 due to some mental health illness , He took some drugs for 3 days . After 5 months , one day between some bad days I drunk some much alcohol. Next day I feel some headache and from nowhere I thought like I will become like my big brother due to drugs. At that time I had the final exams but I was not able to concentrate .I was thinking about the suicide but I talk to my parents about everything except sex issues. After sometime I become normal about the big brother think. But  I thing about sex problems was coming for me. The thing start again in late feb.i was unable to held my anger , talk disrespectly to my real brother and my parents. And then I feel bad for all that.