Tan - you are so far in the opposite direction of a bad mother it is hilarious! You are a GREAT mother!
Don't stress about it (I know, easier said than done!). Sammiejane gave you great advice - exactly what I was going to write.
To make you feel better, DD is always falling and smacking her head. Even head first. She's nose dived off the bed at least half a dozen times (the most recent being this morning ), off the couch, and even off the change table as well! It's life. It's not like you didn't try to stop it or that you threw her off it. You did everything you could to get her to be safe (by sitting rather than standing), you tried to catch the falling missile, you checked her over immediately, you prepared to take her to ED and when noticed she was ok, called a professional advice line (much better than sitting in ED for hours!), you are watching her to make sure she is ok, and you feel bad for her accident. What's wrong with that? NOTHING. She will have a great many more mishaps throughout her life and you can't stop them all. Sometimes they need to have accidents and make mistakes so they can learn from them... even the ones that cause a booboo.

Make yourself a cuppa and watch Izzy running circles and relish in the beautiful, talented, courageous girl you are raising.

MG

P.S. The runs was probably the stress - not uncommon