This is very common problem called as sex anxiety.
Most of people suffering from it have concern about there body features,they have doubt about there performance on bed,sometimes they have bad sexual experience in past or childhood sexual abuse.And secondarily they have depression
so they feel frustrsted and become less of confidence,short tempered.
This can be changed by proper evaluation , counselling
and sos medication.
Please consult nearby Psychologist
for detailed inperson evaluation and treatment.