Getting and maintaining an erection

I'm a 20yr old guy from India. I am into alot of soccer. I recently began having sex 2 months ago. Over the course of time I have realized that I'm finding it harder and harder to get and maintain an erection. I was circumcised as a newborn. I started masturbating when i was 14 and never had erection problems. But in the past few years i have seen the problem set in. I experience a gastric movement and lose my erection immediately without an orgasm. Sometimes i am not able to attain one at all..and at other times, i lose it as soon as i put on a condom. Even the erections I get are mild without a major increae in the penis head size.

Being a medical student there are a few things I guess could be contributing to my problem:
I am used to eating VERY spicy food which includes raw chillies often
I have been having performance related stress
I have severe anger issues
This is my first relationship
I have had trouble coping with my girl-friend's past
She has put on quite some weight since the time we have started going out.
I have tough breast tissue which the doctor examined and declared normal.
I have a moderate form of piles
I am almost always constipated
On sitting for long hours on a chair, i feel my genitals go kinda numb
I use a deodorant powder in my groin and axilla to keep them from sweating too much
I have always masturbated by squeezing the penis base.
My body veins are very very prominent, and on tying a tourniquet often move under the skin


I have been working on my kegel muscles for the last 1 month and haven't really benefited. I plan to use an Indian generic Caverta. Please advice if I am headed in the right way.