Good Afternoon, My Question Is Such That The Embarrassment Associated

Good afternoon,
My question is such that the embarrassment associated with my issue has kept me from seeing a doctor for possible treatment, although the problem has plagued me for over a decade. You see, I am twenty five years old, and since the age of fourteen, I have not been able to maintain, nor even get an erection. This is something that has caused me sever relationship issues as well as personal emotional problems. What's interesting is that I discovered just one year ago that there is one particular brand of the OTC 'male enhancement' supplements frequently found in gas stations that solves that issue for me completely. The trouble is, they're upwards of $30/piece and generally take four to six hours to take effect, making them far from ideal for daily use or to take just when needed. I am curious to know what other solutions may be available to me or what other avenues I may pursue in correcting this issue. Up until I discovered those pills, sex had been a nerve-wracking, anxiety inducing activity and always a negative experience. Although I have found some level of relief since, on occasion these feelings/experiences are revisited, due to not having a pill on hand or not have taken one early enough. Indeed, no way to live. I would really appreciate your input and suggestions. Thank you!