Can someone suggest me to regain this thing. All of a sudden the erection is not happening. I tried lots of stuff but erection is not happening. Am still in my 20's.

Stop thinking about it so much. Stop worrying about it. You're obsessing yourself right into ED.

Do you take medication or anything? My boy takes ADD meds and sometimes it makes it hard (no pun intended lol) to get an erection.. and yes Don't worry too much about it you'll make it worse

Maybe your just stressed.