This is pretty odd, surely they saw your CV before the interview? Perhaps ask your contact at these companies for more feedback?
A CV only tells you so much after all,
Later on, I applied to a different company, and while I got hired...holy shit. I have one hell of an imposer syndrome, because an "average" dev there can seriously show me a trick or two...or a hundred. The top of the food chains might as well be gods among mortals in my view.
So really, a resume only tells you what the applicant THINKS their qualifications are. Nothing more.
1. It's normal.
2. Don't worry.
3. You got the interviews, lots of people didn't. That's a pat on the back there.
4. There are lots of other companies.
5. Focus on your strengths. Keep going, push on, and you can come back to these companies in a year or less with much more strength and steel than now.