Baby fell

My 5 month old fell off the couch. I feel terrible. ThankGod she is ok, but I really feel like trash. She was on the couch chilling on her lounger. I got up to put my cup in the sink for literally 2 seconds and I heard a thump. I ran to her and there she was on the floor in shock and hollering. She calmed down as soon as I picked her up. I have heard from other moms that their babies have fell off beds, chairs, couches etc before. I was even told that it would happen to me at least once. I swore up and down i would never let that happen. Now here we are. Sighhhh. From a first time mom to another .... our babies are at the age where any little movement can potentially be dangerous if not watched closely. Please be careful whether you have experienced this already or not. I still can’t believe i allowed her to fall.