That is very distressing on several levels and is probably not helping you. There are a variety of options available to you – but first, a little information.
There is rapid ejaculation, and then there is premature ejaculation . Premature ejaculation (PE) means that you are ejaculating within one minute of entry. According to the DSM-V, while many men are concerned with PE, only 1% of men actually suffer from it as defined in the medical profession. That being said, I would initially recommend that you see your doctor and/or a urologist. Just have all your plumbing and hardware checked out first. Once you establish that you are healthy, or get a diagnosis and treatment for potential issues, then you can tackle the rest.
I recommend several things to consider when approaching the treatment of longevity in the bedroom. Is it a problem for you, for your partner, or for both of you? If you didn’t previously define it as a problem, talk to your partner about her sexual expectations. See if you two can discover what can be added to enhance the sexual experience for her. However, if you are also distressed by your longevity, ask yourself when the problem began. Was this always a problem or is it a newer occurrence? If this is a recent problem, perhaps something has happened in your life that's affecting your bedroom performance. Do you struggle with anxiety or depression?
There is a fantastic book I recommend to men by Dr. Bernie Zilbergeld called "The New Male Sexuality." It's very informative and detailed and includes some great ideas. But, I’ll just highlight that he discusses at great length a man’s mindset when it comes to sex. Men are prescribed a wide range of mistaken beliefs that society tends to buy into, and then are disappointed when reality doesn’t live up to a Harlequin romance novel. No man is a foot-long steel rod that can pummel a partner all night and achieve orgasm without going soft, all while the partner is actively engaged and climaxing multiple times. Figure out what your realistic expectations for sex are, and what it might take to get there. Also, redefine "sex." There is lots of fun to be had beyond putting a penis in a vagina. Expand the idea into various means of play, foreplay, toys, kink, fantasy, etc.
A final thought is to tune into your own arousal. Discover what turns you on, and what sends you over the edge so quickly. Practice getting turned on and trying to maintain that moderate arousal until you’re ready to come. This will take some time, as you will need to identify your levels of arousal and participate in that while practicing control over not allowing yourself to climax. You can do this by backing off from being aroused, and then getting re-aroused, and then backing off again. There will be times it doesn’t work, and that is OK. You’re trying. Practice makes perfect, right?
You might also consider finding a sex therapist in your area who can assist you through the psychological process, and help you track your progress.