[LvMyYorki]

You just need to keep watching that she is walking normally and giving even pressure to the leg you stepped on. If she is injured she may not cry everytime she takes a step, but she might not be using any pressure on that leg and be overcompensating with her other three. I would definitley run her by the vet to be sure!
You are new to this, but one thing that is imperitive when you get a yorkie and EVERYONE will tell you the same thing.... your "walking" days are over, soon to be replaced with the "Yorkie Shuffle." Youu cant pick your feet up like in the olden pre-york days... you are forever committed to shuffling your feet throught the house. We don't even wear shoes in the house anymore for the very reason you posted. I have a friend that told me of a girlfriend of hers that was getting ready for work and had on high heels and stepped on her puppy and killed it. After she told me that... I have forever stood by the front door for putting on and taking off of the shoes, plus since I have to do the "shuffle" its easier in barefeet!
I'm sure your little pup will be fine, but to ease your mind have her checked out to be safe! AND you are NOT the worst mommy in the world bc we have all done it or fallen on our faces trying to avoid it! I slammed my fingertips in a kitchen drawer this weekend bc Tino was standing under my feet and when I went to moved I lost balance and grabbed a half open drawer that when my weight pushed on it making it close on my hand!!! I was crying it hurt so bad a few of my nailbeds actually bled! BUT the good news is... Tino was fine! He looked up at me like, "what was that all about???" and then went back to chewing his Nylabone!
You are a new mommy and this is how we learn this stuff! Thats why forums are great!