Can't get erections But only morning erections and thanks to masturbation (but I can't keep it hard)

Hi, I'm 19 years old, my situation is complex, I can't get erections when I watch porn, erotic images, in practice everything about sex since May, it was an evening on May 17th, because I hated my penis size (about 14 cm) I wanted to try jelqing, but after 10 minutes I saw that something was wrong, I can have erections thanks to masturbation and sometimes I have morning erections (but it's not so hard and I see that the glans fails to expand to the maximum).
I talk a little about myself, I've known pornography since I was 11 and started masturbating since I was 13, until that May 17th I could have erections easily without problems and I wish I hadn't jelqing that day .
From this Monday I started the NO PMO
Do you recommend a medical examination? and for how many days do you recommend the NO PMO?

 

It's not porn fault, but jelqing fault