Erectile dysfunction?

hello ,i will tell my whole story.i used to masturbate for a long time.but i did it only once in a day.i am now 17.but about 5 months ago i read an article that it is bad.it stated lot of bad effects of it.i was scared to death whem i read that.i thought that my whole world fall in to me.i then searched for anything that can be done about.i found that prostrate massage whould help.i dit it for about 5 days.on the fifth day i found that i can't erect my penis mentall but by hand.i feared to death again.also i had no much interest in sex at that moment.now it is 5 months .i am now suffering from depression.and i am taking treatments.but now there is little plus.but still heavily depressed about that incident.my mind tells me that it could be a prostrate cancer.i want to know can such thing happen with sudden fear.can it be a physical cause.should i be worried.