I recommend that you do a blood test that include those, as well as the serum testosterone level.
A temporary medical therapy can help you bypass this problem.
There are number of reasons that coud lead to this problem. Among the most common causes are psychological ones, mainly "Performance Aniexity", where the male doesn't feel confident enough to achieve the "expected" sexual performance. Please note that the porn industry is based on entertainment and exaggeration; one can't and should NOT compare himself to porn stars, as the parameters set by these films are simply completely wrong and inaccurate.
A number of questions needs answering before jumping into conclusions about the causes of erectile dysfunction. Have you had successful erections before? Are you facing stress, trauma, change of work, sexual partner, is your concern based on comparison among peers?
Try to get out of your box! Try having sex in different locations, go with your partner for a holiday, get away from kids and work stress. Re-define your love life and explore new intimate situations.
Overweight and sedentary lifestyle are among the most common reasons leading to erectile dysfunction. Adopting a healthier lifestyle, excercising regularly, maintaining a healthy weight, eating fresh healthy food can have a magical effect on one's mood and sexual performance.
Certain diseases like diabetes and dyslipidemia can have deteriorating effects on sexual activity. Good regulation of blood sugar, lipid profile and blood pressure is essential for a better performance.
If all these steps fail, then you might be a candidate for a more in depth hormonal investigation, which should be conducted by your urologist.