It's so difficult not to worry, particularly with time on your hands.
I had a C-section, had gestational diabetes and developed high blood pressure towards the end; my son was in the NICU with pneumonia for over 2 weeks; and the whole birth ordeal plus my fluctuating hormones gave me panic attacks so powerful that I couldn't talk, much less walk. I didn't breastfeed (beyond the first days). We gave up on the cloth diapers.
And you know what?
In fact, we're great. My kids are very healthy, tall, happy, engaged, at or ahead of their milestones, and cute as can be. We play and laugh and tell jokes. We're extremely attached, and I celebrate their growing independence.
In the past 18 months I've gone from being terrified and lost and mourning my previous life, to profoundly enjoying motherhood and adoring my children. There are moments when they drive me bananas, but I cherish them.
The best advice I got (besides Vicki Iovine's books, which I enjoyed, and Dr. Sears' medical advice, which I relied upon):
Take it one hour at a time. Becoming a mother is a process, not an event.
You'll be great.