How old are you? And what's your blood pressure like? And how about anxiety? There are a zillion things that can lead to ED problems, and generally speaking, the problems snowball once they start.
I've had issues with it over the last couple years. I'm 32 years old. Every time I had a shitty erection, I would have more anxiety the next time, negative expectations, etc. It fucked with me. Finally decided what the hell, ED meds it is. Since I tried that, I had some amazing sex, and shortly after I had a run of good experiences, I didn't really need it anymore. Got my mind right, and things are back to normal. I'll still use Cialis/Viagra every now and then just for the hell of it, or to be sure of myself, but for me, the mental game was a bigger deal than anything. It's something to consider.
Btw, I tried the things you've already tried. Caber definitely did not work for me.