Talk to Andrologist on Ed Erectile Dysfunction

I have problem staying hard whenever i try to have sex. Sometimes I get full hard on but before penetration it gets flacid and sometimes it's in flaccid at times and don't get fully erect. I'm very stressed now. In mornings naturally it stays fully erect. I have to get married now in some from Gujrat and don't know a doctor here for these issues. Please prescribe me a complete prescription. Please help