Obsessive Compulsive Disorder and ED

I am a 30 year old man in a wonderful monogamous relationship with the most wonderful woman. I also happen to live with Obsessive Complusive Disorder. This issues gives me a lot of very vivid uncomfortable and unwanted thoughts, one of which is the fear of being unable to perform. I have used viagra before to treat this but last night when we were having sex I was having trouble getting hard even with the medication. While we ended up having pleasurable sex I felt embarassed and asked for reassurance which is a compulsion I do when I get anxious.
I also have begun an obsessive fear that I have ruined my chances of getting hard by taking medicine and/ or that I will never be able to get hard again and that I will be left because of that. However, it also has shown to me that my erection issues are completely mental. I just downloaded the app today and I really want to work on building my confidence and helping myself relax so I can get hard but also don’t want to over pressurize myself (my girlfriend is also not pressuring me at all she’s an angel)
Does anyone else struggle with OCD? Does anyone have any tips on relaxation to help get hard ?