Hi.Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern.
As per your symptom you might have
premature ejaculation. LOSS OF ERECTION after EJACULATION is normal phenomenon & not erectile dysfuction. Problem might be that you are ejaculation earlier than normal.
Most cases of premature ejaculation do not have a physical cause & have psychological factors such as
anxiety, guilt,etc. Following steps can be done in premature ejaculation
1.Practicing
relaxation techniques or distraction methods help you delay ejaculation.
2.Have communication with your partner to stop during over-excitement. This will help you delay ejaculation.
3. You can try a different position during intercourse.
4.Counseling/
behavioral therapy help reduce anxiety related to premature ejaculation.
5.There are also creams, gels, and a spray that may be used to treat premature ejaculation by reducing sensation.These medicines are applied to the penis before sex. condoms with pre-applied gels are also available in market.
Visit a doctor , if problem persist.
Don't worry you would be fine
Hope this information helps.