Masturbation. Which food should i take?

Good evening sir I am 25 year's old .i had MASTURBATION habit from 15 years old. At the age of 20 I felt so much pressure and tension for 5-6 months because of love matter with a girl. FROM THAT ONWARDS MY pennis and tests reduced in their size. All the guys are laughing at me by seeing small BULGE in underwear while we taking bath outside. They are KILLING with their words like ARE U MALE? NORMAL TIMES erection is there but the pennis is Macerate (falling) with in 2 minutes. RECENTLY I had sex with a girl by wearing CONDOM but the pennis STOOD only 5 MINUTES after ANOTHER 5 minutes SPERM came out. My problem is I am checking my pennis many times a day whether it is erected or not through pants & also the pennis is only in THUMB size remaining times .also I am feeling pennis size while I am walking i.e low weight of pennis. What happened to me? Which medicines should I take? Which food should I take? I got engagement and I am going to marry with in months. Is I am eligible to sex life