Two week checkup...

I took my son in for his two week checkup today and he isn’t back to birth weight yet. I feel like a failure as a mother. My pediatrician wasn’t too concerned just wants me to wake baby more to feed since he tends to fall asleep in the boob. With my first baby this is the exact reason I gave up breastfeeding because of slow weight gain. I was in tears at the office because I felt like we were doing good but I guess not. Any words of encouragement would be appreciated.