Hi, 
Thanks for posting in HCM. 
I understand your concern. 
What problems you are facing with reference to 
premature ejaculation is more of psychological problem than physical. Most men experience such a thing what you have experienced and described. 
To overcome premature ejaculation, you need to practice behavioral technique like '
pause and squeeze' technique along with use of 
local anaesthetic spray to decrease sensation. 
Intake of selective serotonin reuptake inhibitors (SSRIs) such as 
sertraline would help to delay ejaculation. 
You can also practice 
meditation to keep your mind calm and spend more time during foreplay to increase your confidence.
Slowly, over a period of time, you would gain confidence and can overcome the problem.
Hope the information provided would be helpful. 
All the best.