First, how old are you? If you're under 20, you're totally normal not to last more than a minute. It gets longer time with age & experience. There's all kinds of stuff you can do, but for younger guys, go squeeze one off by yourself earlier in the day, then you'll last longer when you need to. The other thing you can do is to practice being able to tell where your "point of no return" is, and stop for a minute just before you get there. Do that a bunch of times, and you'll train yourself to last a lot longer.
Even at my old-fart age of 42, if I haven't gotten any for a couple weeks, I explode like a 15 year-old as soon as my wife touches me. She hates that.
As far as stuff to keep you ready longer, Viagra or Cialis is fine, as long as you don't have a medical problem with your heart, or other things they warn about. Those stories about eternal hard-ons are VERY VERY rare, and you shouldn't have to worry about it if you take a normal dose of Viagra or Cialis. They just say that so you can't sue the drug company IF it happens to 1 out of 10,000,000 people. And just for the record, they don't amputate your junk. They just stick a needle in it to drain the trapped blood. That is, unless you fail to go for help after 8 or 10 hours.
Charles