Hi, I am 23 years old and I have ED issues since 19. My urologist diagosed me with ED (I didn’t undergo any examination, we just talked), prescribed me Cialis 10 mg and I am taking it 2-3 times a month for over a 2 years now. I buy 20 mg of Cialis (4 tablets), halve them to 8 tablets of Cialis 10 mg. When I first took it it didn’t work. Sometimes I take 10 mg, sometimes 20 mg, couple hours before sex but lately it stopped working. It didn't work properly from the beginning I think, because it got me a erection when I was stimulated but sometimes it disappeared after a while of having sex. In last couple of weeks it got worse. I tried to have sex with my girlfriend (we are together for about a year now) for few times last month, everytime I took Cialis 20 mg (few hours before), and everytime my erection disappeared a moment (1-2 minutes) after penetrating my girlfriend. While on Cialis, everything is fine when she gives me a ******* or a handjob but the moment we are going to have sex, even when I think about it, my heart rate increases and my erection disappears. I am a stresser, my heart rate rises wery easily in some situations. When we are turned on and I start to stimulate her with my fingers or tongue, my erection disappears even if I took Cialis. When I’m not on Cialis I can‘t maitain an erection regarding any sexual activities with my GF sometimes I can but it is not very strong. I can maintain strong lasting erection when I’m alone - watching porn, I could do that few times a day and I have never had problem with this. I started to watch porn at 13 I think and since than I have been watching it daily, sometimes more times a day. I reduced watching of porn to once a week few months ago because I thought it may contribute to my problems. When I first experieced this issue, I was 19 and I watched porn everytime couple hours before we were about to have sex with my (former) girlfried to increase my endurace. I have seen a cardiologist about my increased heart rate, she prescribed me beta blocker and told me I have increased heart rate due to smoking, but I didn’t take it. I have no other medical issues (cvs, hormoes..) and I’m smoking 15 – 20 cigarettes per day for 7 years now. My father, his brother and my grandfather died due to stroke. So my question is: What should I do when Cialis 20 mg is not working properly? Is it cardiovascular or neurological issue? Thank you wery much!