Is it normal for me to be experiencing this at 21?

I am a 21 year old diabetic type 1 insulin dependent diabetic who is experiencing ED for the past 2 years and no actual ejacuation or "nut" when I were to masturbate. My doctor has put me on Cialis which I have taken with two different types of insulin Novilin 70/30 and Lantus. I need to know if my insulin is helping cause the ED as i have been a diabetic since the age of 7 and i went through puberty at age 13 and have had erections and ejaculations fine until these past 3 years. i have also noticed that i have been experienced a decrease in sex drive and weight. I've only been on the cialis 5mg, citalopram 20mg gernic for celexa, and Amitriptylin 25mg Gernic for Elavil i dont really notice a change except when i was taking the cialis which i got maybe 3 good erections in 30 days because of the Cialis but that was a free trial. Its very frustrating because my doctor doesnt really act like he cares about my situation. Im trying to change my diet drastically so i can get my blood sugars in check and im trying to exercise more but still no change in my erections. If there is anything anyone can tell me that can help i would greatly appreciate it.