Nikki, accidents happen unfortunately. It's happened to me and I'm sure similar things have happened to your other kids. Kat rolled off the edge of my bed when she was a bub. Luckily she landed on a pillow. She's also been bouncing on the lounge and gone headfirst into the floor (she was just learning how to jump), walked right off the edge of both the lounge and bed (she knew the edge was there, just forgot and we just didn't reach her in time)..... kids are amazingly resiliant! They get a fright and cry like their hearts are broken, then five minutes later they have forgotten about it. And mummy's kisses always make everything feel better! (add a bottle or a feed and they feel a million dollars!). As long as Chantelle is not hurt, she will forget it (probably already has), it's us who never forget it nor forgive ourselves. But we learn from it.
No-one likes to see their baby fall or get hurt, but it's going to happen....